A 386 is old enough that the bios can't auto-detect the drive, so you have to go into the bios and set the number of sectors and so on, manually. The info should be printed on the drive. Don't forget to save the current parameters so that you can use your ibm drive again later.

Also most 386's can't handle a drive bigger than around 512MB.

I know some BIOSes have a whitelist for hardware components (or rather, component classes) like WLAN cards, restricting use to only those blessed by the manufacturer. Doing something similar to HDDs would be thinkable, but so far I haven't seen it done (at least outside of Sony's locked down "PSX" DVR, which even goes as far as having the drives run custom firmware), and I certainly wouldn't expect it on a vintage 386 class device. Unintentional incompatibility seems more likely to me. edit: And yes, as Robbert suggested above, Hanlon's Razor is also always a good rule to apply :p

Also, be aware that certain BIOSes only support a few fixed CHS combinations:
Re: Olivetti M290-20 looking for the list of supported HDDs

MrAvaronald wrote on 2024-12-17, 12:35:

if I try to change the existing hard drive to another the system won't work anymore.

If you move a drive to a new system, you need to configure drive geometry to be the same. If it's a CHS geometry, that means using the same Cylinders / Heads / Sectors values or if it is LBA addressing, configure the system to use LBA addressing. BIOS older than June 1994 rarely work with values > C:1024/H:16:/S:63 BIOS older than 1997 frequently don't support support LBA addressing or Cylinders > 1024. Devices newer than 2010 often lack CHS compatibility entirely.

If the BIOS in the new system doesn't support the geometry used on the old system, you can configure an XTide Universal Bios image to use the geometry that you want and then put that ROM in your new system.

MrAvaronald wrote on 2024-12-17, 12:35:

gives error beeps (which I don't know the meaning of as there's no manual for the rare mobo) or gets past mem test and freezes afterwards.

freeze after mem test can be BIOS too old for drive size, but beep codes is not bios related.
Not powering on correctly might be ATA1 IDE pin 28 change from BALE to CSEL issue Re: "Fixed" 386sx motherboard works but not with 16-bit VGA card