1. Peter (as switck) wrote the broken #ifndef guard in libngu (Jan 2021). 2. Peter (as doc-hex) integrated libngu into #Coldcard firmware and changed seed generation to use it (March 2021). 3. The combination caused ngu.random.bytes() → MicroPython Yasmarang software PRNG (seeded from UID + timers) instead of the hardware TRNG. Result: seeds with ~40 bits effective entropy on Mk2/Mk3 (and ~72 bits on later models that mixed in some secure-element data), which "attackers" later brute-forced. #Bitcoin