TOS 1.04 Cause Floppy malfunction?

[ChrisA]

Hi

I've just upgraded the TOS on my STFM to the Rainbow 1.04, using the six rom set purchased here. Previously I had a disk with Sundog on it which was just about the only one of all my floppy disks to still work. Now the ST can't read it. When I format a 720k floppy on a PC and copy files to it the ST can not read it, if I try to format a previously working disk from a PC on the ST it fails and becomes unusable both on the ST or PC. I have another ST disk which the ST reads ok sporadically.

Is there something I may have missed or broken when taking the ST apart during the TOS upgrade or is this just coincidence?

Any ideas much appreciated. Thanks.