diff --git a/lib/glacier/CMakeLists.txt b/lib/glacier/CMakeLists.txt
index 253a089..befd857 100644
--- a/lib/glacier/CMakeLists.txt
+++ b/lib/glacier/CMakeLists.txt
@@ -1,6 +1,8 @@
 add_library(glacier STATIC
   string/string.cpp
+  string/string_builder.cpp
   string/string_view.cpp
+  string/str_format.cpp
   string/str_split.cpp
   )
 
diff --git a/lib/glacier/container/vector.h b/lib/glacier/container/vector.h
index 874e1ab..e66864a 100644
--- a/lib/glacier/container/vector.h
+++ b/lib/glacier/container/vector.h
@@ -57,6 +57,8 @@ class Vector {
   uint64_t size() const { return size_; }
   uint64_t capacity() const { return capacity_; }
 
+  const T* RawPtr() const { return data_; }
+
  private:
   T* data_;
   uint64_t size_;
diff --git a/lib/glacier/string/str_format.cpp b/lib/glacier/string/str_format.cpp
new file mode 100644
index 0000000..abe3c93
--- /dev/null
+++ b/lib/glacier/string/str_format.cpp
@@ -0,0 +1,73 @@
+#include "glacier/string/str_format.h"
+
+namespace glcr {
+
+namespace {
+
+void StrFormatNumber(StringBuilder& builder, uint64_t value, uint64_t base) {
+  const char* kHexCharacters = "0123456789ABCDEF";
+
+  if (value < base) {
+    builder.PushBack(kHexCharacters[value]);
+    return;
+  }
+
+  StrFormatNumber(builder, value / base, base);
+
+  builder.PushBack(kHexCharacters[value % base]);
+}
+
+}  // namespace
+
+template <>
+void StrFormatValue(StringBuilder& builder, uint8_t value, StringView opts) {
+  StrFormatValue(builder, static_cast<uint64_t>(value), opts);
+}
+
+template <>
+void StrFormatValue(StringBuilder& builder, uint16_t value, StringView opts) {
+  StrFormatValue(builder, static_cast<uint64_t>(value), opts);
+}
+
+template <>
+void StrFormatValue(StringBuilder& builder, int32_t value, StringView opts) {
+  StrFormatValue(builder, static_cast<uint64_t>(value), opts);
+}
+
+template <>
+void StrFormatValue(StringBuilder& builder, uint32_t value, StringView opts) {
+  StrFormatValue(builder, static_cast<uint64_t>(value), opts);
+}
+
+template <>
+void StrFormatValue(StringBuilder& builder, uint64_t value, StringView opts) {
+  if (opts.find('x') != opts.npos) {
+    builder.PushBack("0x");
+    StrFormatNumber(builder, value, 16);
+  } else {
+    StrFormatNumber(builder, value, 10);
+  }
+}
+
+template <>
+void StrFormatValue(StringBuilder& builder, ErrorCode value, StringView opts) {
+  StrFormatValue(builder, static_cast<uint64_t>(value), opts);
+}
+
+template <>
+void StrFormatValue(StringBuilder& builder, const char* value,
+                    StringView opts) {
+  StrFormatValue(builder, StringView(value), opts);
+}
+
+template <>
+void StrFormatValue(StringBuilder& builder, StringView value, StringView opts) {
+  StrFormatInternal(builder, value);
+}
+
+void StrFormatInternal(StringBuilder& builder, StringView format) {
+  // TODO: Consider throwing an error if there are unhandled format
+  builder.PushBack(format);
+}
+
+}  // namespace glcr
diff --git a/lib/glacier/string/str_format.h b/lib/glacier/string/str_format.h
new file mode 100644
index 0000000..c1753e5
--- /dev/null
+++ b/lib/glacier/string/str_format.h
@@ -0,0 +1,62 @@
+#pragma once
+
+#include "glacier/memory/move.h"
+#include "glacier/status/error.h"
+#include "glacier/string/string_builder.h"
+#include "glacier/string/string_view.h"
+
+namespace glcr {
+
+template <typename T>
+void StrFormatValue(StringBuilder& builder, T value, StringView opts);
+
+template <>
+void StrFormatValue(StringBuilder& builder, uint8_t value, StringView opts);
+
+template <>
+void StrFormatValue(StringBuilder& builder, uint16_t value, StringView opts);
+
+template <>
+void StrFormatValue(StringBuilder& builder, int32_t value, StringView opts);
+
+template <>
+void StrFormatValue(StringBuilder& builder, uint32_t value, StringView opts);
+
+template <>
+void StrFormatValue(StringBuilder& builder, uint64_t value, StringView opts);
+
+template <>
+void StrFormatValue(StringBuilder& builder, ErrorCode value, StringView opts);
+
+template <>
+void StrFormatValue(StringBuilder& builder, const char* value, StringView opts);
+
+template <>
+void StrFormatValue(StringBuilder& builder, StringView value, StringView opts);
+
+void StrFormatInternal(StringBuilder& builder, StringView format);
+
+template <typename T, typename... Args>
+void StrFormatInternal(StringBuilder& builder, StringView format, T value,
+                       Args... args) {
+  uint64_t posl = format.find('{');
+  uint64_t posr = format.find('}', posl);
+  if (posl == format.npos || posr == format.npos) {
+    // TODO: Consider throwing an error since we still have values to consume.
+    return StrFormatInternal(builder, format);
+  }
+
+  builder.PushBack(format.substr(0, posl));
+  StrFormatValue(builder, value, format.substr(posl + 1, posr - posl - 1));
+  StrFormatInternal(builder, format.substr(posr + 1, format.size() - posr - 1),
+                    args...);
+}
+
+template <typename... Args>
+StringBuilder StrFormat(StringView format, Args... args) {
+  StringBuilder builder;
+  StrFormatInternal(builder, format, args...);
+  return glcr::Move(builder);
+}
+
+}  // namespace glcr
diff --git a/lib/glacier/string/string_builder.cpp b/lib/glacier/string/string_builder.cpp
new file mode 100644
index 0000000..aa4d2d5
--- /dev/null
+++ b/lib/glacier/string/string_builder.cpp
@@ -0,0 +1,24 @@
+#include "glacier/string/string_builder.h"
+
+namespace glcr {
+
+void StringBuilder::PushBack(const StringView& str) {
+  if (capacity() < size() + str.size()) {
+    uint64_t new_capacity = capacity() == 0 ? 1 : capacity() * 2;
+    while (new_capacity < size() + str.size()) {
+      new_capacity *= 2;
+    }
+    Resize(new_capacity);
+  }
+  for (uint64_t i = 0; i < str.size(); i++) {
+    Vector<char>::PushBack(str[i]);
+  }
+}
+
+String StringBuilder::ToString() const { return String(RawPtr(), size()); }
+
+StringBuilder::operator StringView() const {
+  return StringView(RawPtr(), size());
+}
+
+}  // namespace glcr
diff --git a/lib/glacier/string/string_builder.h b/lib/glacier/string/string_builder.h
new file mode 100644
index 0000000..6e31bcb
--- /dev/null
+++ b/lib/glacier/string/string_builder.h
@@ -0,0 +1,26 @@
+#pragma once
+
+#include "glacier/container/vector.h"
+#include "glacier/string/string.h"
+#include "glacier/string/string_view.h"
+
+namespace glcr {
+
+class StringBuilder : public Vector<char> {
+ public:
+  StringBuilder() : Vector<char>() {}
+  StringBuilder(const StringBuilder&) = delete;
+  StringBuilder(StringBuilder&& str) : Vector<char>(Move(str)) {}
+
+  void PushBack(const StringView& str);
+  using Vector<char>::PushBack;
+
+  String ToString() const;
+
+  // Note that this could become invalidated
+  // at any time if more characters are pushed
+  // onto the builder.
+  operator StringView() const;
+};
+
+}  // namespace glcr
diff --git a/lib/glacier/string/string_view.cpp b/lib/glacier/string/string_view.cpp
index 0295fd0..1f33519 100644
--- a/lib/glacier/string/string_view.cpp
+++ b/lib/glacier/string/string_view.cpp
@@ -25,6 +25,7 @@ uint64_t StringView::size() const { return size_; }
 bool StringView::empty() const { return size_ == 0; }
 
 char StringView::at(uint64_t pos) const { return value_[pos]; }
+char StringView::operator[](uint64_t pos) const { return at(pos); };
 
 uint64_t StringView::find(char c, uint64_t pos) const {
   for (uint64_t i = pos; i < size_; i++) {
diff --git a/lib/glacier/string/string_view.h b/lib/glacier/string/string_view.h
index 7c51f07..e7f2112 100644
--- a/lib/glacier/string/string_view.h
+++ b/lib/glacier/string/string_view.h
@@ -19,6 +19,7 @@ class StringView {
   bool empty() const;
 
   char at(uint64_t pos) const;
+  char operator[](uint64_t pos) const;
 
   uint64_t find(char c, uint64_t pos = 0) const;
 
diff --git a/lib/libc/CMakeLists.txt b/lib/libc/CMakeLists.txt
index 569bea0..a7249a0 100644
--- a/lib/libc/CMakeLists.txt
+++ b/lib/libc/CMakeLists.txt
@@ -1,7 +1,6 @@
 
 add_library(c STATIC
   src/malloc.cpp
-  src/stdio.cpp
   src/string.cpp
   )
 
diff --git a/lib/libc/include/stdio.h b/lib/libc/include/stdio.h
deleted file mode 100644
index e5d6904..0000000
--- a/lib/libc/include/stdio.h
+++ /dev/null
@@ -1,10 +0,0 @@
-#pragma once
-
-#include <stdarg.h>
-
-// int fprintf(FILE *stream, const char *format, ...);
-int printf(const char *format, ...);
-int sprintf(char *str, const char *format, ...);
-// int vfprintf(FILE *stream, const char *format, va_list arg);
-int vprintf(const char *format, va_list arg);
-int vsprintf(char *str, const char *format, va_list arg);
diff --git a/lib/libc/src/stdio.cpp b/lib/libc/src/stdio.cpp
deleted file mode 100644
index 23931e8..0000000
--- a/lib/libc/src/stdio.cpp
+++ /dev/null
@@ -1,126 +0,0 @@
-#include "stdio.h"
-
-#include <stdint.h>
-
-namespace {
-
-uint32_t num_chars(uint64_t num, uint8_t base) {
-  uint32_t width = 0;
-  while (num > 0) {
-    num /= base;
-    width++;
-  }
-  return width;
-}
-
-int sprint_base(char *str, uint64_t num, uint32_t base) {
-  uint32_t width = num_chars(num, base);
-  if (width == 0) {
-    *str = '0';
-    return 1;
-  }
-
-  uint64_t place = 1;
-  while (num > 0) {
-    // FIXME: We seem to have an issue with loading globals.
-    const char *kHexChars = "0123456789abcdef";
-    str[width - place] = kHexChars[num % base];
-    place++;
-    num /= base;
-  }
-
-  return width;
-}
-
-}  // namespace
-
-int sprintf(char *str, const char *format, ...) {
-  va_list arg;
-  va_start(arg, format);
-  int ret = vsprintf(str, format, arg);
-  va_end(arg);
-  return ret;
-}
-
-int vsprintf(char *str, const char *format, va_list arg) {
-  uint32_t chars = 0;
-  while (*format != '\0') {
-    if (*format != '%') {
-      *str = *format;
-      chars++;
-      str++;
-      format++;
-      continue;
-    }
-    format++;
-    switch (*format) {
-      case '%':
-        *(str++) = *(format++);
-        chars++;
-        break;
-      case 'l': {
-        switch (*(++format)) {
-          case 'x': {
-            int width = sprint_base(str, va_arg(arg, uint64_t), 16);
-            if (width == -1) {
-              return -1;
-            }
-            chars += width;
-            str += width;
-            format++;
-            break;
-          }
-          case 'u': {
-            int width = sprint_base(str, va_arg(arg, uint64_t), 10);
-            if (width == -1) {
-              return -1;
-            }
-            chars += width;
-            str += width;
-            format++;
-            break;
-          }
-        }
-        break;
-      }
-
-      case 'x': {
-        int width = sprint_base(str, va_arg(arg, uint32_t), 16);
-        if (width == -1) {
-          return -1;
-        }
-        chars += width;
-        str += width;
-        format++;
-        break;
-      }
-      case 'u': {
-        int width = sprint_base(str, va_arg(arg, uint32_t), 10);
-        if (width == -1) {
-          return -1;
-        }
-        chars += width;
-        str += width;
-        format++;
-        break;
-      }
-      case 's': {
-        char *instr = va_arg(arg, char *);
-        int width = 0;
-        while (*instr != '\0') {
-          *(str++) = *(instr++);
-          width++;
-        }
-        format++;
-        break;
-      }
-      default:
-        *(str++) = *(format++);
-        chars++;
-    }
-  }
-  *str = '\0';
-  chars++;
-
-  return chars;
-}
diff --git a/lib/mammoth/include/mammoth/debug.h b/lib/mammoth/include/mammoth/debug.h
index 29a5767..6cbc7d5 100644
--- a/lib/mammoth/include/mammoth/debug.h
+++ b/lib/mammoth/include/mammoth/debug.h
@@ -1,9 +1,17 @@
 #pragma once
 
+#include <glacier/string/str_format.h>
+#include <glacier/string/string_view.h>
 #include <stdint.h>
 #include <ztypes.h>
 
-void dbgln(const char* fmt, ...);
+// TODO: Take StringView here instead.
+void dbgln(const glcr::StringBuilder& builder);
+
+template <typename... Args>
+void dbgln(const glcr::StringView& fmt, Args... args) {
+  dbgln(StrFormat(fmt, args...));
+}
 
 // Checks that the code is ok.
 // if not exits the process.
diff --git a/lib/mammoth/src/debug.cpp b/lib/mammoth/src/debug.cpp
index e1e7045..f415ca2 100644
--- a/lib/mammoth/src/debug.cpp
+++ b/lib/mammoth/src/debug.cpp
@@ -1,27 +1,11 @@
 #include "include/mammoth/debug.h"
 
 #include <glacier/status/error.h>
-#include <stdarg.h>
-#include <stdio.h>
 #include <zcall.h>
 
-void dbgln_internal(const char* str) {  // Safe to ignore the result since right
-                                        // now this doesn't throw.
-  uint64_t _ = ZDebug(str);
-}
-
-void dbgln(const char* fmt, ...) {
-  char str[1024];
-  va_list arg;
-  va_start(arg, fmt);
-  int ret = vsprintf(str, fmt, arg);
-  va_end(arg);
-
-  if (ret == -1 || ret > 1024) {
-    crash("Bad vsprintf", 1);
-  }
-
-  dbgln_internal(str);
+void dbgln(const glcr::StringBuilder& builder) {
+  glcr::String str = builder.ToString();
+  (void)ZDebug(str.cstr());
 }
 
 void check(uint64_t code) {
@@ -44,10 +28,10 @@ void check(uint64_t code) {
       dbgln("Unhandled code");
       break;
   }
-  ZProcessExit(code);
+  (void)ZProcessExit(code);
 }
 
 void crash(const char* str, uint64_t code) {
   dbgln(str);
-  ZProcessExit(code);
+  (void)ZProcessExit(code);
 }
diff --git a/lib/mammoth/src/endpoint_server.cpp b/lib/mammoth/src/endpoint_server.cpp
index 6059f8d..17c46d7 100644
--- a/lib/mammoth/src/endpoint_server.cpp
+++ b/lib/mammoth/src/endpoint_server.cpp
@@ -26,7 +26,7 @@ void EndpointServer::ServerThread() {
         ZEndpointRecv(endpoint_cap_, &message_size, recieve_buffer_, &num_caps,
                       nullptr, &reply_port_cap));
     if (err != glcr::OK) {
-      dbgln("Error in receive: %x", err);
+      dbgln("Error in receive: {x}", err);
       continue;
     }
 
@@ -35,7 +35,7 @@ void EndpointServer::ServerThread() {
     // FIXME: Consider pumping these errors into the response as well.
     check(HandleRequest(request, response));
     if (!response.HasWritten()) {
-      dbgln("Returning without having written a response. Req type %x",
+      dbgln("Returning without having written a response. Req type {x}",
             request.request_id());
     }
   }
diff --git a/lib/mammoth/src/init.cpp b/lib/mammoth/src/init.cpp
index 56a441e..66ca38a 100644
--- a/lib/mammoth/src/init.cpp
+++ b/lib/mammoth/src/init.cpp
@@ -23,30 +23,25 @@ z_err_t ParseInitPort(uint64_t init_port_cap) {
     RET_ERR(ret);
     switch (init_sig) {
       case Z_INIT_SELF_PROC:
-        dbgln("received proc");
         gSelfProcCap = init_cap;
         break;
       case Z_INIT_SELF_VMAS:
-        dbgln("received vmas");
         gSelfVmasCap = init_cap;
         break;
       case Z_INIT_ENDPOINT:
         gInitEndpointCap = init_cap;
         break;
       case Z_BOOT_DENALI_VMMO:
-        dbgln("received denali");
         gBootDenaliVmmoCap = init_cap;
         break;
       case Z_BOOT_VICTORIA_FALLS_VMMO:
-        dbgln("received victoria falls");
         gBootVictoriaFallsVmmoCap = init_cap;
         break;
       case Z_BOOT_PCI_VMMO:
-        dbgln("received pci");
         gBootPciVmmoCap = init_cap;
         break;
       default:
-        dbgln("Unexpected init type %x, continuing.", init_sig);
+        dbgln("Unexpected init type {}, continuing.", init_sig);
     }
   }
 
diff --git a/sys/denali/ahci/ahci_device.cpp b/sys/denali/ahci/ahci_device.cpp
index 73f60f3..78a80ce 100644
--- a/sys/denali/ahci/ahci_device.cpp
+++ b/sys/denali/ahci/ahci_device.cpp
@@ -56,20 +56,20 @@ glcr::ErrorCode AhciDevice::IssueCommand(Command* command) {
 }
 
 void AhciDevice::DumpInfo() {
-  dbgln("Comlist: %lx", port_struct_->command_list_base);
-  dbgln("FIS: %lx", port_struct_->fis_base);
-  dbgln("Command: %x", port_struct_->command);
-  dbgln("Signature: %x", port_struct_->signature);
-  dbgln("SATA status: %x", port_struct_->sata_status);
-  dbgln("Int status: %x", port_struct_->interrupt_status);
-  dbgln("Int enable: %x", port_struct_->interrupt_enable);
+  dbgln("Comlist: {x}", port_struct_->command_list_base);
+  dbgln("FIS: {x}", port_struct_->fis_base);
+  dbgln("Command: {x}", port_struct_->command);
+  dbgln("Signature: {x}", port_struct_->signature);
+  dbgln("SATA status: {x}", port_struct_->sata_status);
+  dbgln("Int status: {x}", port_struct_->interrupt_status);
+  dbgln("Int enable: {x}", port_struct_->interrupt_enable);
 
   // Just dump one command info for now.
   for (uint64_t i = 0; i < 32; i++) {
-    dbgln("Command Header: %u", i);
-    dbgln("Command %x", command_list_->command_headers[i].command);
-    dbgln("PRD Len: %x", command_list_->command_headers[i].prd_table_length);
-    dbgln("Command Table %lx",
+    dbgln("Command Header: {}", i);
+    dbgln("Command {x}", command_list_->command_headers[i].command);
+    dbgln("PRD Len: {x}", command_list_->command_headers[i].prd_table_length);
+    dbgln("Command Table {x}",
           command_list_->command_headers[i].command_table_base_addr);
   }
 }
@@ -94,23 +94,27 @@ void AhciDevice::HandleIrq() {
     // Device to host.
     DeviceToHostRegisterFis& fis = received_fis_->device_to_host_register_fis;
     if (fis.fis_type != FIS_TYPE_REG_D2H) {
-      dbgln("BAD FIS TYPE (exp,act): %x, %x", FIS_TYPE_REG_D2H, fis.fis_type);
+      dbgln("BAD FIS TYPE (exp,act): {x}, {x}",
+            static_cast<uint64_t>(FIS_TYPE_REG_D2H),
+            static_cast<uint64_t>(fis.fis_type));
       return;
     }
     if (fis.error) {
-      dbgln("D2H err: %x", fis.error);
-      dbgln("status: %x", fis.status);
+      dbgln("D2H err: {x}", fis.error);
+      dbgln("status: {x}", fis.status);
     }
   }
   if (int_status & 0x2) {
     // PIO.
     PioSetupFis& fis = received_fis_->pio_set_fis;
     if (fis.fis_type != FIS_TYPE_PIO_SETUP) {
-      dbgln("BAD FIS TYPE (exp,act): %x, %x", FIS_TYPE_PIO_SETUP, fis.fis_type);
+      dbgln("BAD FIS TYPE (exp,act): {x}, {x}",
+            static_cast<uint64_t>(FIS_TYPE_PIO_SETUP),
+            static_cast<uint64_t>(fis.fis_type));
       return;
     }
     if (fis.error) {
-      dbgln("PIO err: %x", fis.error);
+      dbgln("PIO err: {x}", fis.error);
     }
   }
 }
diff --git a/sys/denali/ahci/ahci_driver.cpp b/sys/denali/ahci/ahci_driver.cpp
index 658b9ee..1b9f72a 100644
--- a/sys/denali/ahci/ahci_driver.cpp
+++ b/sys/denali/ahci/ahci_driver.cpp
@@ -75,7 +75,7 @@ void AhciDriver::DumpCapabilities() {
   if (caps & 0x4'0000) {
     dbgln("AHCI mode only");
   }
-  dbgln("Speed support: %u", (caps & 0xF0'0000) >> 20);
+  dbgln("Speed support: {}", (caps & 0xF0'0000) >> 20);
   if (caps & 0x100'0000) {
     dbgln("Command list override");
   }
@@ -130,7 +130,7 @@ void AhciDriver::DumpPorts() {
     }
 
     dbgln("");
-    dbgln("Port %u:", i);
+    dbgln("Port {}:", i);
     dev->DumpInfo();
   }
 }
@@ -143,7 +143,7 @@ void AhciDriver::InterruptLoop() {
     for (uint64_t i = 0; i < 32; i++) {
       if (devices_[i] != nullptr && devices_[i]->IsInit() &&
           (ahci_hba_->interrupt_status & (1 << i))) {
-        dbgln("Interrupt for %u", i);
+        dbgln("Interrupt for {}", i);
         devices_[i]->HandleIrq();
         ahci_hba_->interrupt_status &= ~(1 << i);
       }
diff --git a/sys/victoriafalls/fs/ext2/ext2_driver.cpp b/sys/victoriafalls/fs/ext2/ext2_driver.cpp
index 6c275bc..ff8de3a 100644
--- a/sys/victoriafalls/fs/ext2/ext2_driver.cpp
+++ b/sys/victoriafalls/fs/ext2/ext2_driver.cpp
@@ -63,23 +63,23 @@ glcr::ErrorOr<glcr::Vector<DirEntry>> Ext2Driver::ReadDirectory(
 
   glcr::Vector<DirEntry> directory;
   for (uint64_t i = 0; i < real_block_cnt; i++) {
-    dbgln("Getting block %lx", inode->block[i]);
+    dbgln("Getting block {x}", inode->block[i]);
     ASSIGN_OR_RETURN(MappedMemoryRegion block,
                      ext2_reader_->ReadBlock(inode->block[i]));
     uint64_t addr = block.vaddr();
     while (addr < block.vaddr() + ext2_reader_->BlockSize()) {
       DirEntry* entry = reinterpret_cast<DirEntry*>(addr);
       directory.PushBack(*entry);
-      glcr::String name(entry->name, entry->name_len);
+      glcr::StringView name(entry->name, entry->name_len);
       switch (entry->file_type) {
         case kExt2FtFile:
-          dbgln("FILE (0x%x): %s", entry->inode, name.cstr());
+          dbgln("FILE (0x{x}): {}", entry->inode, name);
           break;
         case kExt2FtDirectory:
-          dbgln("DIR  (0x%x): %s", entry->inode, name.cstr());
+          dbgln("DIR  (0x{x}): {}", entry->inode, name);
           break;
         default:
-          dbgln("UNK  (0x%x): %s", entry->inode, name.cstr());
+          dbgln("UNK  (0x{x}): {}", entry->inode, name);
       }
       addr += entry->record_length;
     }
diff --git a/sys/victoriafalls/victoriafalls.cpp b/sys/victoriafalls/victoriafalls.cpp
index 25919ba..8e54c52 100644
--- a/sys/victoriafalls/victoriafalls.cpp
+++ b/sys/victoriafalls/victoriafalls.cpp
@@ -15,7 +15,7 @@ uint64_t main(uint64_t init_cap) {
   Empty empty;
   DenaliInfo denali_info;
   RET_ERR(yellowstone.GetDenali(empty, denali_info));
-  dbgln("LBA (recv): %u", denali_info.lba_offset());
+  dbgln("LBA (recv): {x}", denali_info.lba_offset());
   ScopedDenaliClient denali(denali_info.denali_endpoint(),
                             denali_info.device_id(), denali_info.lba_offset());
   ASSIGN_OR_RETURN(Ext2Driver ext2, Ext2Driver::Init(glcr::Move(denali)));
diff --git a/sys/victoriafalls/victoriafalls_server.cpp b/sys/victoriafalls/victoriafalls_server.cpp
index dd2deb7..0b9f48d 100644
--- a/sys/victoriafalls/victoriafalls_server.cpp
+++ b/sys/victoriafalls/victoriafalls_server.cpp
@@ -28,7 +28,7 @@ glcr::ErrorCode VFSServer::HandleOpenFile(const OpenFileRequest& request,
         ASSIGN_OR_RETURN(files, driver_.ReadDirectory(files.at(j).inode));
       }
     }
-    dbgln("Directory '%s' not found.", glcr::String(path_tokens.at(i)).cstr());
+    dbgln("Directory '{}' not found.", glcr::String(path_tokens.at(i)).cstr());
     return glcr::NOT_FOUND;
   }
 
@@ -43,7 +43,7 @@ glcr::ErrorCode VFSServer::HandleOpenFile(const OpenFileRequest& request,
     }
   }
   if (!region) {
-    dbgln("File '%s' not found.",
+    dbgln("File '{}' not found.",
           glcr::String(path_tokens.at(path_tokens.size() - 1)).cstr());
   }
 
diff --git a/sys/yellowstone/hw/gpt.cpp b/sys/yellowstone/hw/gpt.cpp
index 7266102..5bf4845 100644
--- a/sys/yellowstone/hw/gpt.cpp
+++ b/sys/yellowstone/hw/gpt.cpp
@@ -66,36 +66,36 @@ glcr::ErrorCode GptReader::ParsePartitionTables() {
       MappedMemoryRegion::FromCapability(resp.memory());
   uint16_t* mbr_sig = reinterpret_cast<uint16_t*>(lba_1_and_2.vaddr() + 0x1FE);
   if (*mbr_sig != 0xAA55) {
-    dbgln("Invalid MBR Sig: %x", *mbr_sig);
+    dbgln("Invalid MBR Sig: {x}", *mbr_sig);
     return glcr::FAILED_PRECONDITION;
   }
   MbrPartition* first_partition =
       reinterpret_cast<MbrPartition*>(lba_1_and_2.vaddr() + 0x1BE);
   if (first_partition->boot_indicator != 0) {
-    dbgln("Boot indicator set: %u", first_partition->boot_indicator);
+    dbgln("Boot indicator set: {}", first_partition->boot_indicator);
     return glcr::FAILED_PRECONDITION;
   }
   if (first_partition->os_type != 0xEE) {
-    dbgln("Incorrect OS type: %x", first_partition->os_type);
+    dbgln("Incorrect OS type: {x}", first_partition->os_type);
     return glcr::FAILED_PRECONDITION;
   }
-  dbgln("LBAs: (%x, %x)", first_partition->starting_lba,
+  dbgln("LBAs: ({x}, {x})", first_partition->starting_lba,
         first_partition->ending_lba);
 
   // FIXME: Don't hardcode sector size.
   ParititionHeader* header =
       reinterpret_cast<ParititionHeader*>(lba_1_and_2.vaddr() + 512);
 
-  dbgln("signature %lx", header->signature);
+  dbgln("signature {}", header->signature);
 
   uint64_t num_partitions = header->num_partitions;
   uint64_t entry_size = header->parition_entry_size;
   uint64_t num_blocks = (num_partitions * entry_size) / 512;
 
-  dbgln("lba_partition_entries %lx", header->lba_partition_entries);
-  dbgln("num_partitions: %x", num_partitions);
-  dbgln("partition_entry_size: %x", entry_size);
-  dbgln("Num blocks: %x", num_blocks);
+  dbgln("lba_partition_entries {x}", header->lba_partition_entries);
+  dbgln("num_partitions: {x}", num_partitions);
+  dbgln("partition_entry_size: {x}", entry_size);
+  dbgln("Num blocks: {x}", num_blocks);
 
   req.set_device_id(0);
   req.set_lba(header->lba_partition_entries);
@@ -108,11 +108,11 @@ glcr::ErrorCode GptReader::ParsePartitionTables() {
     PartitionEntry* entry = reinterpret_cast<PartitionEntry*>(
         part_table.vaddr() + (i * entry_size));
     if (entry->type_guid_low != 0 || entry->type_guid_high != 0) {
-      dbgln("Entry %u", i);
-      dbgln("T Guid: %lx-%lx", entry->type_guid_high, entry->type_guid_low);
-      dbgln("P Guid: %lx-%lx", entry->part_guid_high, entry->part_guid_low);
-      dbgln("LBA: %lx, %lx", entry->lba_start, entry->lba_end);
-      dbgln("Attrs: %lx", entry->attributes);
+      dbgln("Entry {}", i);
+      dbgln("T Guid: {x}-{x}", entry->type_guid_high, entry->type_guid_low);
+      dbgln("P Guid: {x}-{x}", entry->part_guid_high, entry->part_guid_low);
+      dbgln("LBA: {x}, {x}", entry->lba_start, entry->lba_end);
+      dbgln("Attrs: {x}", entry->attributes);
       // For now we hardcode these values to the type that is
       // created in our setup script.
       // FIXME: Set up our own root partition type guid at some
diff --git a/sys/yellowstone/hw/pcie.cpp b/sys/yellowstone/hw/pcie.cpp
index 19b2c8d..e5aaa14 100644
--- a/sys/yellowstone/hw/pcie.cpp
+++ b/sys/yellowstone/hw/pcie.cpp
@@ -18,7 +18,7 @@ PciReader::PciReader() {
   dbgln("Creating addr space");
   uint64_t vaddr;
   check(ZAddressSpaceMap(gSelfVmasCap, 0, gBootPciVmmoCap, &vaddr));
-  dbgln("Addr %lx", vaddr);
+  dbgln("Addr {x}", vaddr);
 
   dbgln("Dumping PCI");
   PciDump(vaddr);
@@ -41,8 +41,8 @@ void PciReader::FunctionDump(uint64_t base, uint64_t bus, uint64_t dev,
     return;
   }
   dbgln(
-      "[%u.%u.%u] (Vendor, Device): (%x, %x), (Type, Class, Sub, PIF): (%u, "
-      "%x, %x, %x)",
+      "[{}.{}.{}] (Vendor, Device): ({x}, {x}), (Type, Class, Sub, PIF): ({}, "
+      "{x}, {x}, {x})",
       bus, dev, fun, hdr->vendor_id, hdr->device_id, hdr->header_type,
       hdr->class_code, hdr->subclass, hdr->prog_interface);
 
@@ -50,7 +50,7 @@ void PciReader::FunctionDump(uint64_t base, uint64_t bus, uint64_t dev,
     dbgln("FIXME: Handle PCI to PCI bridge.");
   }
   if (hdr->class_code == 0x1) {
-    dbgln("SATA Device at: %lx", reinterpret_cast<uint64_t>(hdr) - base);
+    dbgln("SATA Device at: {x}", reinterpret_cast<uint64_t>(hdr) - base);
     achi_device_offset_ = reinterpret_cast<uint64_t>(hdr) - base;
   }
 }
diff --git a/sys/yellowstone/yellowstone.cpp b/sys/yellowstone/yellowstone.cpp
index fab4494..05284b5 100644
--- a/sys/yellowstone/yellowstone.cpp
+++ b/sys/yellowstone/yellowstone.cpp
@@ -1,3 +1,4 @@
+#include <glacier/string/str_format.h>
 #include <mammoth/debug.h>
 #include <mammoth/endpoint_client.h>
 #include <mammoth/init.h>
@@ -16,8 +17,8 @@ glcr::ErrorCode SpawnProcess(z_cap_t vmmo_cap, z_cap_t yellowstone_cap) {
 }
 
 uint64_t main(uint64_t port_cap) {
-  dbgln("Yellowstone Initializing.");
   check(ParseInitPort(port_cap));
+  dbgln("Yellowstone Initializing.");
 
   ASSIGN_OR_RETURN(auto server, YellowstoneServer::Create());
   Thread server_thread = server->RunServer();
@@ -45,7 +46,7 @@ uint64_t main(uint64_t port_cap) {
   glcr::String file(reinterpret_cast<const char*>(filemem.vaddr()),
                     response.size());
 
-  dbgln("Test: '%s'", file.cstr());
+  dbgln("Test: '{}'", file.cstr());
 
   check(server_thread.Join());
   dbgln("Yellowstone Finished Successfully.");
diff --git a/sys/yellowstone/yellowstone_server.cpp b/sys/yellowstone/yellowstone_server.cpp
index 39b767b..f1be0ce 100644
--- a/sys/yellowstone/yellowstone_server.cpp
+++ b/sys/yellowstone/yellowstone_server.cpp
@@ -90,7 +90,7 @@ glcr::ErrorCode YellowstoneServer::HandleRegisterEndpoint(
     vfs_client_ = glcr::MakeShared<VFSClient>(victoria_falls_cap_);
     check(has_victoriafalls_mutex_.Release());
   } else {
-    dbgln("[WARN] Got endpoint cap type: %s", req.endpoint_name().cstr());
+    dbgln("[WARN] Got endpoint cap type: {}", req.endpoint_name().cstr());
   }
   return glcr::OK;
 }
diff --git a/yunq/server.cpp.jinja b/yunq/server.cpp.jinja
index 00ba26b..358ce83 100644
--- a/yunq/server.cpp.jinja
+++ b/yunq/server.cpp.jinja
@@ -52,7 +52,7 @@ void {{interface.name}}ServerBase::ServerThread() {
     recv_cap.Reset();
     glcr::ErrorCode recv_err = static_cast<glcr::ErrorCode>(ZEndpointRecv(endpoint_, &recv_buf_size, recv_buffer.RawPtr(), &recv_cap_size, recv_cap.RawPtr(), &reply_port_cap));
     if (recv_err != glcr::OK) {
-      dbgln("Error in receive: %x", recv_err);
+      dbgln("Error in receive: {x}", recv_err);
       continue;
     }
 
@@ -69,7 +69,7 @@ void {{interface.name}}ServerBase::ServerThread() {
       reply_err = static_cast<glcr::ErrorCode>(ZReplyPortSend(reply_port_cap, kHeaderSize + resp_length, resp_buffer.RawPtr(), resp_cap.UsedSlots(), resp_cap.RawPtr()));
     }
     if (reply_err != glcr::OK) {
-      dbgln("Error in reply: %x", reply_err);
+      dbgln("Error in reply: {x}", reply_err);
     }
   }