Files
vt1200/harness/udpstream
arti baffb8292e udpstream: osboot -- jump to the OS cold start (0x3F5788C0), the path that quietens the LANCE
The reset vector is the wrong entry: it starts POST, which re-programs the
board window from a state a payload has already changed.  The firmware has a
second entry, 0x3F5788C0, where the boot gate at 0x3F2042D0 branches when it
skips level 1.  It begins with DINT, CSR0=STOP on the LANCE, and a board-window
re-program -- exactly what a takeover breaks.

MAME, from the LANCE access log: the payload's last access and the OS's first
are 130 us apart, then pc=3F578940 writes CSR0=0x0004 (STOP) and pc=3FDDCAE0
(the OS driver) re-initialises the chip, after which the OS keeps servicing it.

cmd 6 / vtcmd.py osboot.  Unit run pending; the report section is 73.
2026-10-30 17:10:45 +02:00
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