Hi!
I replaced two ram chip and had to recalibrate from scratch the floppy
on the right. The spring that pushes the dummy felt head on top of the
floppy disk had become a bit loose, and there wasn't enough pressure on
the disk, so I got BOOT ERROR message.
I had to bend the spring a little and rotate the felt head...
http://www.supervinx.com/Retrocomputer/Osborne/1/
Notice the graphic package :P