diff --git a/firmware/src/commands.c b/firmware/src/commands.c
index 4a71afc..51b8a8f 100644
--- a/firmware/src/commands.c
+++ b/firmware/src/commands.c
@@ -6,13 +6,9 @@
 
 #include <string.h>
 #include <stdbool.h>
-#include <stdio.h>
 #include <stdlib.h>
 #include <util/delay.h>
 
-// Internal function prototypes
-void _uartPutAsciiBlock(DataBuffer buffer);
-
 // Mode: ASCII (false) or binary (true)
 bool binary_mode = false;
 
@@ -127,25 +123,17 @@ void commandRead(char* arg) {
             }
         } else {
             // Fancy ASCII output
-            _uartPutAsciiBlock(buffer);
+            uartPrintf("<%d>", buffer.bytes);
+
+            for (int i = 0; i < buffer.bytes; i++) {
+                uartPrintf(" %02X", buffer.data[i]);
+            }
+            uartPutLine(NULL);
         }
 
     } while (buffer.bytes > 0);
 }
 
-void _uartPutAsciiBlock(DataBuffer buffer) {
-    char outBuffer[20];
-    sprintf(outBuffer, "<%d>", buffer.bytes);
-    uartPutString(outBuffer);
-
-    for (int i = 0; i < buffer.bytes; i++) {
-        sprintf(outBuffer, " %02X", buffer.data[i]);
-        uartPutString(outBuffer);
-    }
-
-    uartPutLine(NULL);
-}
-
 void commandWrite(char* arg) {
     if (arg == NULL) {
         uartPutLine("ERR WRITE needs a start address");
@@ -176,26 +164,20 @@ void commandErase() {
 
 // TESTREAD command: for testing purposes, reads a few bytes and returns them in a human readable format.
 void commandTestRead() {
-    uint8_t byte;
-    char outBuffer[20];
-
     eepromSetReadMode();
 
     for (int i = 0x00; i < 0x20; i++) {
-        itoa(i, outBuffer, 16);
-        uartPutString("TESTREAD 0x");
-        uartPutString(outBuffer);
-        uartPutString(": ");
+        uartPrintf("TESTREAD 0x%02X: ", i);
 
-        byte = eepromReadByte(i);
-        itoa(byte, outBuffer, 16);
+        uint8_t byte = eepromReadByte(i);
 
-        uartPutChar(byte);
-        uartPutString(" (0x");
-        uartPutString(outBuffer);
-        uartPutString(")");
+        if (byte >= 32 && byte <= 126) {
+            uartPutChar(byte);
+        } else {
+            uartPutChar('?');
+        }
 
-        uartPutLine(NULL);
+        uartPrintf(" (0x%02X)\n");
     }
 }
 
diff --git a/firmware/src/uart.c b/firmware/src/uart.c
index b68bab2..1d6fcba 100644
--- a/firmware/src/uart.c
+++ b/firmware/src/uart.c
@@ -2,6 +2,8 @@
 #include "uart.h"
 
 #include <avr/io.h>
+#include <stdarg.h>
+#include <stdio.h>
 #include <util/setbaud.h>
 
 // Initialize UART
@@ -54,6 +56,19 @@ void uartPutLine(char* data) {
     uartPutChar('\n');
 }
 
+// Transmit a sprintf formatted string (maximum buffer: 256 bytes!)
+void uartPrintf(const char* format, ...) {
+    char outBuffer[256];
+
+    va_list args;
+    va_start(args, format);
+
+    vsprintf(outBuffer, format, args);
+    uartPutString(outBuffer);
+
+    va_end(args);
+}
+
 // Receive a single character (blocking)
 unsigned char uartGetChar() {
     // Block until a character has been received
diff --git a/firmware/src/uart.h b/firmware/src/uart.h
index b47c953..7421af4 100644
--- a/firmware/src/uart.h
+++ b/firmware/src/uart.h
@@ -16,6 +16,9 @@ void uartPutString(char* data);
 // Transmit a string followed by a line break
 void uartPutLine(char* data);
 
+// Transmit a sprintf formatted string (maximum buffer: 256 bytes!)
+void uartPrintf(const char* format, ...);
+
 // Read a single character (blocking)
 unsigned char uartGetChar();