Describe the bug
XTIDE fails to boot from the hard drive on any 8088/8086 machine with the NEC V20/V30 selected. Only booting is affected - using the disk after booting from floppy works perfectly.

Reproducible with both r622 (current in the ROM set) and r624 (latest) versions of the XTIDE BIOS; both the regular XT and the V20/V30/80186/80188-specific version (ide_xtp.bin) are affected.

Bisecting has shown that this issue has first appeared in the build 4147 with the commit e6321d9.

Tested with:

• IBM XT (1986) - Error 40h;
• AMI XT clone - Error 40h;
• Compaq Portable - no error displayed, just skips;
• Super PC/Turbo XT - no error displayed, just skips;
• Xi8088 - Error 1h;
• Amstrad PC1512 - Error 1h;
• Olivetti M24 - Error 1h.

To Reproduce
Steps to reproduce the behavior:

1. Select any 8088 or 8086 machine;
2. Select PC/XT XTIDE as the hard drive controller;
3. Attach a HDD with an OS installed to IDE (0:0);
4. Start the machine, wait for XTIDE and observe the error

Expected behavior
XTIDE successfully booting off a HDD.

Screenshots

Desktop (please complete the following information):

• OS: Windows 10
• 86Box version: v3.11 builds 4311 and 4320
• Build information: old dynarec, 32-bit, regular

Additional context
To help reproduce the problem, a config file (using the IBM XT 1986), a bootable HDD, and prepared ROMs of the r624 version of the XTIDE BIOS are included in the archive below:

xtide.zip