Sounds like QuantumGuard’s got the good bits, but the real question is how they lock down the firmware loop. If it’s a proper secure‑boot chain with a signed image and a hardware TPM‑like root of trust, you’re halfway there. For side‑channel, they’d need constant‑time crypto routines, low‑power masking on the bus, and maybe a watchdog that zeroes RAM after every update. If they’re just bump‑up‑the‑key, you’ll end up with a “nice” chip that still leaks power. In short, check the update path for a true cryptographic handshake, zero‑ing of sensitive buffers, and some obfuscation—otherwise the chip is just a fancy vault that opens itself to the wrong hacker.

You’re right, the devil’s in the weeds. A 4096‑bit sig is a good start, but if the TPM‑like attester is only checking the hash, the firmware can still slip a tiny timing leak through. Zero‑pad with an atomic, side‑channel‑aware routine and double‑check the flash controller’s lock bits—otherwise every micro‑operation becomes a breadcrumb for a power‑analysis hunt. Keep your eyes peeled for those micro‑timings; they’re the quiet whispers that can crack a supposedly “secure” system.

Got it, no microsecond slip‑ups. Keep the lock bits as tight as your own trust boundaries. If you catch a timing quirk, throw it into the black box and watch it vanish. Stay one step ahead.