XT-IDE/XT-CF cards do work in the IBM 5170, but not if the 5170 motherboard has the first BIOS revision. Your motherboard does not have the first BIOS revision, and so no problem there.
Adding an XT-IDE/XT-CF card to an IBM 5170 is akin to adding a SCSI card.
The XT-IDE/XT-CF card will coexist with the 5170's stock floppy/hard controller. That is discussed, with diagram, in the second section of [
here].
The default settings, which equate to: {Base address of ROM at C8000, Base I/O address of 300h, ROM enabled}
In relation to the card's ROM, the lo-tech web page contains, "
Regardless of the chip used, the first 32KB only will be mapped into the PC address space."
So, with a starting address of C8000 (a.k.a. C800:0)(a.k.a. C800), the range of addresses used by the card is C8000 through CFFFF.
That will
conflict with anything starting at CF000, and explains an error message (generated by ???) along the lines that CF000 is unavailable.
{Base address of ROM at D8000, Base I/O address of 320h, ROM enabled}
The range of addresses used by the ROM becomes D8000 through DFFFF, which explains an error message (generated by ???) along the lines that DA000 is unavailable.
So there is a conflict between the XT-CF-lite's ROM and something else.
I did a search for "unavailable" in the source code of the ROM content, which is the XTIDE Universal BIOS (XUB), and "unavailable" does not appear.
Are you aware of anything in your 5170 that might be causing the conflict?