What happened?

Since build 5472 and onward, Windows NT 4.0 is unable to boot into graphics mode when a Mach32 card is used (regardless of PCI/ISA, and regardless of video memory/RAMDAC options, as far as I can tell). The entire emulator becomes unresponsive while hanging on a distorted blue and black screen, leaving the user to force close/terminate it. Selecting VGA Mode from the boot menu does not help. The last working build is 5471.

(The bad cropping in the image is my own, not a fault of the emulator. Unable to take a screenshot via the emulator proper since the process hangs.)

Steps to reproduce:

1. Start the emulator and observe the hang, no interaction required.

Link to VM, pass is 86box

Configuration file

[General]
vid_renderer = qt_software

[Machine]
machine = ym430tx
cpu_family = pentium_p54c
cpu_speed = 90000000
cpu_multi = 1.5
cpu_use_dynarec = 1
fpu_softfloat = 0
time_sync = local
fpu_type = internal
mem_size = 32768

[Video]
gfxcard = mach32_pci

[Input devices]
mouse_type = ps2

[Sound]
fm_driver = nuked

[Network]
net_01_link = 0
net_02_link = 0
net_03_link = 0
net_04_link = 0

[Storage controllers]
hdc = internal
cassette_mode = load

[Hard disks]
hdd_01_parameters = 63, 16, 1560, 0, ide
hdd_01_fn = /path/to/regression-5472/c.vhd
hdd_01_vhd_blocksize = 4096
hdd_01_speed = ramdisk
hdd_01_ide_channel = 0:0

[Floppy and CD-ROM drives]
fdd_01_type = none
fdd_02_type = none
cdrom_01_speed = 72
cdrom_01_parameters = 1, atapi
cdrom_01_ide_channel = 0:1
cdrom_01_type = 86BOX_CD-ROM_1.00

Operating system

Fedora Linux 39

CPU

AMD Ryzen 5 5560U

86Box version

v4.1 build 5472

Build architecture

Linux - x64 (64-bit)

Build type

• New recompiler
• Debug build

Download source

Official website (Jenkins, GitHub)

Additional context

The issue doesn't seem to happen with Windows 9x.