I meant the color classic with system 7.5 lost its mind when using the 400 k disk, yes you are correct it won't boot system 1.0. The plus booted but thats when it bombed.

Been a while since I messed with 400 k disks but these were what came with that dead motherboard 128, apple branded ones. So I was just seeing what was on them. Finder 1.0 but tell the system.