CDTV ROM Upgrade debugging

Hi,

I'm new to all this, I recently got a CDTV and have been putting in upgrades. I have 8MB FastMem in the diagnostic port, SCSI extension, 4 Floppy drives and now wanted to update the Kickstart ROM.

I bought CDTV ROMs V2.30 and a Kickstart 3.1 ROM to go with it from eBay.
Put the CDTV-ROMs in, boots fine with the old Kickstart 1.3, CDs work, RAM works and so on. But when I put in the 3.1 ROM, I get a white screen and nothing else. The LCD front display also doesn't show the time anymore with the 3.1 ROM but the number 9 (maybe an error code?).

From reading other people's experiences when the CDTV ROMs are incompatible, I expected the Kickstart 3.1 screen to show and the CD drive not to work, but this seems different. I also tried the Kickstart ROM in an A500+ and it wouldn't boot. Did I just get unlucky and got a bad ROM chip? A friend was able to read the chip and I compared the md5sum of the resulting image and it matches Kickstart 3.1 rev 40.63 so I would expect the chip is fine, but maybe reading it messed it up?

I also have images of the CDTV ROM chips, but I couldn't find any checksums of them online to compare to, but as I said, they seem to work just fine with the 1.3 Kickstart.

I'm hoping someone here has an idea