Root cause: vpx_max_postboot_acks=200, a Phase-2 bring-up guard, capped how many post-boot replies the device would ever feed. A real BattleTech session issues an unbounded stream of sync/frame/render replies and aborted with "velocirender_receive timed out - sends_wo_rcv" at exactly the 200th ack (143 sync + 55 frame-ack + 2 render). Cap is now effectively unlimited (0x7fffffff; override VPX_MAX_ACKS for diagnostics). After the fix the full game (game.conf, RIO disabled, cycles=max) runs indefinitely: 2500+ syncs, 1264+ frame-acks, no abort, into L4VIDEO content load (Thor mech + terrain from ALPHA_1/REL410/BT/VIDEO/GEO -- 841 real .bgf models; test.egg is only mission params). Window still shows background: the game uses the full DPL hierarchy (instance/object/lod/geogroup + DCS transforms) which the flat flyk-tuned scene walk doesn't traverse yet -- that is Phase 3d, documented in PHASE3-PROGRESS.md. Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
VPX device — DOSBox-X integration
Our original source for the emulated Division VPX link adapter. Kept here under
version control because the DOSBox-X source tree itself
(emulator/src/, ~490 MB) is git-ignored.
vpxlog.cpp— Phase 1 logging device. Impersonates the INMOS C012 link adapter at I/O base0x150, answers status reads so the game keeps transmitting, and logs every access to$VPXLOG. (Phase 2 will grow this into a responding transputer-monitor + i860-loader + frame-stream renderer, or fork into a separatevpx.cpp.)
Applying to a DOSBox-X source checkout
Tested against DOSBox-X v2026.06.02, MSYS2 mingw64.
- Copy the device in:
cp emulator/vpx-device/vpxlog.cpp emulator/src/src/hardware/vpxlog.cpp - Add it to the hardware build — in
src/src/hardware/Makefile.am, appendvpxlog.cpptolibhardware_a_SOURCES(we inserted it afterglide.cpp). - Call the init — in
src/src/gui/sdlmain.cpp, declarevoid VPXLOG_Init();next to the other*_Init()prototypes and callVPXLOG_Init();right afterGLIDE_Init();in the machine bring-up sequence. - Build:
Output:
cd emulator/src ./build-mingw-sdl2 --enable-debug=heavysrc/src/dosbox-x.exe.
Running
set VPXLOG=C:\VWE\TeslaRel410\emulator\vpxlog.txt
emulator\src\src\dosbox-x.exe -conf emulator\capture.conf
python emulator\analyze_capture.py
With VPXLOG unset the device is inert and the build behaves like stock
DOSBox-X.