Disassembled BTL4OPT.EXE (PE-in-DOS32RTM) to crack the last unknowns: - velocirender_sync (@0x48D220): sends action 0x2D with a data token and checks cmp token, reply.node[0] (the 'unexpected action' text only prints the action; the real check is the echoed token). Device now echoes the token in node[0]. Sync passes. - Speculative-poll gating: only feed a reply after consecutive empty polls (a blocking inRecord spin), not single handle_iserver_stuff() checks. - Frame-ack: velocirender_frameack expects action 9 (vr_draw_scene); device tracks outstanding draw_scene and replies 9. Frame-ack passes. The game now passes sync, loads renderer config, builds the scene (create/flush/list_add/draw_scene), completes frame-ack, and enters its own content loader (L4VIDEO.cpp) loading BattleTech models. Remaining issues are content packaging/paths and an empty DPL config -- not VPX protocol. The board emulation is functionally complete for boot + scene setup + frame-ack. Co-Authored-By: Claude Fable 5 <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.