They were drawn at y=850, overlapping the REST text row (846-867), which is
what shows as a stray box over REST in the unit photo. The text panel already
reports OK as YES/NO.
.text went from 0x018C6140 to 0x018CACD0, so the marker cells at 0x018C8000
landed inside the payload's own code; cell() then overwrote instructions and
the CPU faulted with an illegal opcode before drawing anything.
MARK moved to 0x018D0000 (~2.6 KB past the end of .text).
The restore wrote 0x0042 into 0x23CC50, overwriting the driver's RDP pointer
(0x05800000); the next CSR access then targeted 0x0042 and the terminal died
with an illegal opcode. The TX kick does move @0x23CC50,a3 / move *a3,a5 --
it reads the live CSR0 and ORs TDMD, there is no shadow cell.
Report: section 10 corrected, section 62 added with the disassembly and the
consequence.
The panel now draws labelled hex text instead of 16 white boxes: a 5x7 glyph
table for 0-9/A-F plus the letters the labels need, built at runtime because
this toolchain never runs .cinit. Rows: CSR0, CSR1, TMD1, RMD1, MCNT, OK and
REST (CSR0 after handing the chip back), on a 32px pitch.
The restore now matches the firmware's own init: CSR0 = 0x7F41
(INIT | INEA | all status bits write-1-to-clear) instead of a plain INIT, then
poll IDON, then 0x0042 (STRT | INEA), plus a retry if TXON does not come up and
an update of the driver's CSR0 shadow cell 0x23CC50.
Note: on the first post-fix run the network still did not recover, so the
restore remains a convenience at best; results are read from the panel.
harness/mame/NETWORK_REPORT.md: how the VT1200 firmware drives the LANCE,
from ROM disassembly and MAME traces. 50 sections, each claim tied to a bit
address, a trace count or a quoted source line. Covers the driver device
struct (0x23CBF0), init (0x3F9D4BC0), descriptor/DMA encoding, the live
handler (0x3F9D5B40) with per-status-bit dispatch, the RX poll (0x3F9D62B0),
ring arming (0x3F9D36C0), TX completion (0x3F9D8AF0) and the single transmit
path every protocol uses (0x3F6084E0 -> 0x3F9DC890 -> 0x3F9D4BC0), plus the
IP protocol dispatch (0x3F6270F0), ICMP (343-count chain), TCP state tables
and live TIME_WAIT, the ARP responder (0x3F6119A0) and the socket 4-tuple
demux confirmed by a memory dump.
It also records what was withdrawn: five successive explanations for the
real-silicon CSR0=0x1BB / TMD1=0x8338 result, and the descriptor-length
encoding bug found by comparing Linux 7990.c and NetBSD am7990.c (length must
be 0xF000 | -len; MAME masks the difference in get_buf_length).
harness/udpstream: the LANCE loopback/takeover payload and the variants used
to test the init/kick orderings in MAME (bare TDMD, STOP before INIT, double
INIT, long wait with CSR0 sampling, IDON clear, corrected descriptor length).
build-lance.sh takes LANCE_SRC/LANCE_OUT so the variants build from one script.
arti