The -d flag tells the script to , stripping away all the 512-byte block headers and stitching the data payloads into a single, continuous binary image. Method B: Online and Native Extractors
Unlike raw binary ( .bin ) or Hex ( .hex ) files, UF2 files are structured in . Each block contains: A magic number (to identify it as UF2).
The first step in decompiling a UF2 is usually converting it back into a standard binary. The official Microsoft UF2 GitHub repository provides a Python script called uf2conv.py .
A true UF2 decompiler would need to:
The raw binary code destined for the flash memory. Magic End Number: A final 32-bit constant ( 0x0AB16F30 ).
Specific byte sequences at the start and end of the block to validate the file format.
The starting address of the flash memory on the target chip. Common Flash Base Addresses: Raspberry Pi Pico (RP2040): 0x10000000 (XIP Flash) Microchip/Atmel SAMD21/SAMD51: 0x00000000 STM32 Series: 0x08000000 uf2 decompiler
: If you are working specifically with the RP2040 (Raspberry Pi Pico), you can use the official picotool save --all all.bin command while the board is in bootloader mode to save the entire flash content directly to a binary file. 2. Decompiling the Extracted Binary
The raw binary chunks destined for the microcontroller.
The easiest method for many: Flash the UF2 onto a development board, then use a debugger (like openocd or pyOCD ) to dump the entire flash memory back to a .bin file. The -d flag tells the script to ,
[ UF2 File ] ➔ (1. Unpacker / Converter) ➔ [ Raw BIN / ELF ] ➔ (2. Disassembler) ➔ [ Assembly ] ➔ (3. Decompiler) ➔ [ C / Pseudocode ] 1. Unpacking (UF2 to BIN Extraction)
A unique identifier for the target microcontroller architecture (e.g., 0xe48bff56 for the RP2040).
Embedded C code interacts directly with hardware registers to control GPIO pins, SPI, I2C, or UART buses. By cross-referencing observed memory reads/writes with the target microcontroller's datasheet, you can identify function purposes. The first step in decompiling a UF2 is
This article explains how to "decompile" or extract raw binary code from a UF2 file and the tools available in 2026 to reverse engineer it.