Now that you have firmware.bin, you have raw machine code. This is where the real reverse engineering begins.
Technically, a UF2 file is just a wrapper. It wraps binary blobs (raw machine code) into a transport format. Therefore, the process of "decompiling" a UF2 file is actually a two-step pipeline:
If you are a security researcher, a hobbyist trying to recover lost source code, or a developer debugging why a specific firmware behaves strangely, you need to bridge the gap between the container format and the logic inside.
On the Raspberry Pi Pico, when you plug it in while holding the BOOTSEL button, it mounts as a drive. The UF2 file you drag onto it overwrites the flash. uf2 decompiler
Before opening Ghidra, you must know the target CPU. The UF2 header often contains a Family ID that reveals this.
If the UF2 is for a Raspberry Pi Pico (RP2040), the architecture is ARM Cortex-M0+ (little endian).
Let's walk through a real example. Assume you have blink.uf2 for an RP2040 (Raspberry Pi Pico). Now that you have firmware
Step 1: Extract the binary
git clone https://github.com/microsoft/uf2
cd uf2/utils
python3 uf2conv.py blink.uf2 --convert --output blink.bin
Step 2: Determine the flash offset
For RP2040, flash starts at 0x10000000. The binary starts at offset 0 within the UF2 payloads.
Step 3: Load into Ghidra
Step 4: Analyze
Step 5: Read the pseudocode
You will see functions like gpio_set_function, sleep_ms, and loops toggling a GPIO pin. You won't see digitalWrite(LED_BUILTIN, HIGH), but you will see *(uint32_t*)(0xd0000000 + 0x24) = 1.
Step 6: (Optional) Rename & Document
In Ghidra, you can rename FUN_10001234 to toggle_led. The decompiler will propagate your name. This is manual reverse engineering. If you are a security researcher, a hobbyist
The UF2 (USB Flashing Format) is a file format developed by Microsoft for flashing microcontrollers (e.g., Arduino, CircuitPython, Raspberry Pi RP2040) over USB mass storage. A "UF2 decompiler" is not a traditional decompiler (source code recovery) but rather a tool to disassemble, extract, and analyze binary data embedded within UF2 files. This report defines the UF2 structure, the need for decompilation, and a practical implementation strategy.
Some UF2 images are not linear. They may have gaps for QSPI flash caches. The raw binary may be correct, but the decompiler sees jumps to addresses that have no code. Use binwalk -E to detect entropy and find real code sections.