March 2, 2026
Freeze spray, hotter takes
An Interesting Find: STM32 RDP1 Decryptor
A $20 dongle ‘unlocks’ protected chips — devs torn between “old news” and “uh-oh”
TLDR: A cheap USB dongle reportedly reads data from “locked” STM32 chips, working out of the box despite sketchy software. Commenters split between “this was always possible” and “uh-oh for gadget makers,” with calls for a teardown and debates over whether it’s true decryption or just a clever bypass.
A mystery blue USB stick from a Chinese marketplace claims to pull secrets out of “locked” STM32 chips (the tiny brains inside tons of gadgets). The buyer tried it and, yes, it dumped the data from a protected chip. No freezer spray theatrics needed, despite the instructions suggesting it. The catch? The Windows app set off antivirus alarms and only ran after switching to Chinese system settings — and the tool weirdly “read” past the chip’s memory, padding with blank data. Still, the real bits were correct.
Cue the comment section meltdown. One camp is smug: this is known — people cite past tricks that can bypass RDP1 (a mid-level lock) and say RDP2 (the permanent lock) is the real fortress. Another camp is alarmed: which industries should worry? Folks name-check smart gadgets, e-bikes, 3D printers, drones — anywhere a cloned firmware could mean copycats and security risks. There’s even a mini–word war: stop calling it “decryption,” say the purists; it’s a readout bypass, not crypto. Conspiracy spice: a top comment hints some chips ship with more memory than advertised, explaining the “overshoot.”
The vibes? “Windows Defender screamed, so it must work,” jokes one user. Others demand a teardown of the scraped-off mystery chip. Freeze spray optional. Hot takes mandatory.
Key Points
- •A low-cost device from Xianyu claims to bypass STM32 RDP1 on F0/F1/F2/F4 series and was purchased for ~150 yuan (~19 EUR).
- •The package included a USB programmer and adapter PCBs; the user supplied 0.1 µF VCAP capacitors and set BOOT1 pull-down.
- •The Windows utility triggered Windows Defender and required Chinese (Simplified, Mainland China) non-Unicode encoding to run.
- •On an STM32F205RBT6, the tool successfully dumped RDP1-protected flash; it read past 128 KB, padding with 0xFF, but valid contents were correct.
- •Prior RDP1 bypass methods (voltage glitching, Exception(al) Failure, Cold-Boot Stepping) are known; this tool offers a turnkey approach, though its internals were not analyzed.