IIRC, though, doesn't Apple HDSC Setup automatically determine the correct interleave to use on the machine you're running? I think thats what I read in MacAddict a few years back, anyway...

Click to expand...

This is really the strange thing that occurs :

When I start Apple HD SC Setup on the Mac Plus, with my two disks connected (the one that is able to boot and the other one), tytping Command-I on the "bad" HD, I got an interlaved "2" appearing in the window; bingo : I start the init process... and after a while, I still got an interleave of "1" on that disk. Same try with 3.

By the way the disk that is able to boot with 4.2 GB is also formatted with interleave 1

Thanks for the advice