I have not specifically tried writing on a 400K disk with a machine that can't natively write to MFS volumes by virtue of the OS. I suppose I could try installing 8.6 on the Duo 230/100 but I only have 20MB of RAM and it is the only machine I have.
Otherwise, it sounds like you have a disk image that can't be properly read. Since you have the hardware, why not try mounting it in Mini vMac and see if it detects it (use a duplicate), if not you may have more work to do, or it is corrupted. Either way I cover quite a bit about disk images in my signature in the More Info section.
Otherwise, it sounds like you have a disk image that can't be properly read. Since you have the hardware, why not try mounting it in Mini vMac and see if it detects it (use a duplicate), if not you may have more work to do, or it is corrupted. Either way I cover quite a bit about disk images in my signature in the More Info section.