ATI Mach64 VT2 256-colors mode is broken under Windows 2000 RTM

[Cacodemon345]

Describe the bug
ATI Mach64 VT2 256-colors mode is broken under Windows 2000 RTM. Icons are drawn improperly and are pure black, with white squares surrounding them.

To Reproduce
Steps to reproduce the behavior:

1. Set up a machine with ATI Mach64 VT2 video adapter selected.
2. Install Windows 2000 RTM
3. Install built-in ATI Mach64 VT2 drivers if not already done.
4. If 256 colors mode isn't selected, select it from the Display Settings.
5. See icons being black and even the Start button glitching in some cases.

Expected behavior
Icons should be drawn properly.

Screenshots

Desktop (please complete the following information):

• OS: Fedora Linux 37
• 86Box version: Build 4371
• Build information: Old dynarec x64

Additional context
None.

[TC1995]

Does it happen before my long time ago changes of the mach64? also, try, if you can, the x86 old dynarec one.