It looks like I'm not the only who has had issue with an XT-IDE on a Tandy machine. I've got one that I've flashed both in basic XT mode as well AT + fast mode, at ports 300/308 and 320/328, boot device port 80/81, with everything always jumpered accordingly. Boot device is a 512 megabyte flash DOM with DOS 6.22 installed using another machine. Whenever I go to boot my Tandy 1000 TL, it always skips the XT-IDE boot BIOS. If I exit Deskmate and execute Restart.com on the flash C: drive, it will boot the XT-IDE BIOS and then lock the system shortly after it recognizes the installed flash DOM. Keyboard is unresponsive, implying there's a resource conflict. Any ideas what witchcraft I've brought upon myself?
EDIT: Downloaded the absolute latest code from the XT-IDE repository, tricked MINGW32 into working correctly, rebuilt all the BIOS files and configurator executable, reconfigured the basic XT BIOS, and now DOS is booting. I was even able to run the SETUPTL file I had hand-dropped on the DOM to configure the machine to boot from the XT-IDE rather than straight to Deskmate. Now it's time to see how advanced of a BIOS I can flash and still have the machine run.
SUPEREDIT: Successfully have the XT-IDE running in fast mode with the 8088-plus (V20) BIOS. Went through some shenanigans to install Duke Nukem on the drive using another PC, then played it on the Tandy using an "Ultimate EGA+" card and a Tandy CoCo 3 -> Genesis controller adapter, which worked with a six-button pad without having to hold down the Mode button at boot or anything like that. I guess next adventures would be in acquiring a nice 8-bit VGA card, installing Windows 3.0 and DeskMate, and experimenting with Ethernet over serial and laplink data transfer.
I spend my days fighting with clunky software so I can afford to spend my evenings fighting with clunky hardware.