This command seems to be not clearly documented (I'm not the only one with this problem)... with the right string, it takes three seconds to delete a MBR partition, when I spend three DAYS to find the good one (partly thanks to a previous forum on MorphZone)...

So, e.g., in the case of a device, master in the second IDE port (=disk@1.0), with the MBR partition on sector 0 (seems to be the rule ??), the right sentence is:
HDMBRClear ide.device 2 0

(ide.device 0, 1, "2", 3...) ;)

An other thing: this command, with others, isn't copied from Mos boot cd to the HD during installation... I don't know if there's a special reason for that...???

At all, it sould be good to make it a bit clear in MorphOS.readme for the next 1.5 release! ;))

Ciao!