Four controlled experiments characterize it: 72-byte frame times out
at CMD53 after the slave advertised credits; bus width/clock/power
save have no effect; removing dhcpc stretches MTBF ~5min -> ~13min.
Slave-side peripheral stall, upstream bug. Device self-heals in ~15s.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
