March 25, 2026 · 15 min read
MerakiMR18PythonJTAGOpenWrtUARTdeep-dive
Launching the kernel and catching failsafe on the way down
Started from the bottom now we here, started from the bottom now my whole team here
Post 10 ended with a verified binary in clean DRAM. Post 5 gave the high-level failsafe saga. This post covers the actual code: the launch trampoline, the regression that taught me to stop touching the CPU, and two competing strategies for triggering failsafe mode.
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March 25, 2026 · 27 min read
MerakiMR18PythonUARTOpenWrtdeep-dive
Hex-encoding 7 million bytes because the PHY won’t cooperate
Slow grind, patience on the line / twenty minutes on the wire just to make it mine
Post 6 described the hex-over-UART transfer protocol at a high level—hex-encode every byte, pipe it through an awk decoder on the MR18, pray nothing goes wrong for 20 minutes straight. This post rips open send_binary.py and uart_transfer.py and walks through the actual Python. Two scripts, two transfer sizes, same dumb protocol, very different engineering challenges.
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