I did a similar thing in the 90s with a big box of faulty ethernet cards - they caused Windows 95 to lock up and the vendor had shipped us replacements telling

I did a similar thing in the 90s with a big box of faulty ethernet cards - they caused Windows 95 to lock up and the vendor had shipped us replacements telling us to throw out the old ones. I was curious and put a card into a Linux box which started throwing a bunch of kernel messages about spurious interrupts but the network card worked OK. Turns out they to they had a bug with the IRQ setting (they were one of the more expensive cards to be configured via a DOS utility instead of jumpers) and would send an interrupt on every IRQ pin regardless of the setting. In the end I used a bench drill to break the trace for all IRQ lines except IRQ 10 and gave them away to friends.