...No amount of creative mount lists ever got my first 600 to work with a hard drive. So I bought another that did. I must have a dozen 600s. Don't use them...
http://www.commodore-amiga-retro.com/amiga/amiga_scuzz93.htm
Correct me if I'm wrong, but I believe there were two reasons, maybe more, that some A600s were not HD compatible out of the box.
1 Some A600s shipped with versions of the ROM (37.299?) without HD or PCMCIA support. Incredible! Version 37.350 and later support large HDs and the PCMCIA port. It's a simple chip swap.
2. For reasons known only to Commodore, they included the IDE HD connector on all A600s, BUT, took one pin (the one that carries the BUSY signal to the HD LED) out of the header on those machines without the "A600HD" label. It probably cost them extra money to disable some A600s in this fashion.