make sure to follow morphOS instructions.. from the morphOS page
ACube Sam460
The Sam460 supports installation both via CDROM and via SD card inserted into the internal SD card slot of the Sam460. We recommend installing from CD where possible.
via CD
Turn on your Sam460.
When prompted to do so by the firmware, press enter on the keyboard to activate the boot selection menu.
When the boot selection menu appears, press enter again to activate the boot device menu. From this menu either choose '3x12 SATA DVD' or '3114 SATA DVD' depending on which SATA controller your optical drive is connected to. If you are not sure, then try first the one and then the other.
Press enter to confirm your choice in the boot device menu, then escape and enter again to select 'boot this configuration'.
MorphOS will now start booting. Once it is done booting, follow the on-screen instructions.
via SD card
Download morphos-3.17-hybrid.hdimg.
Write morphos-3.17-hybrid.hdimg to an SD card directly as a disk image.
Insert the SD card into your Sam460's internal SD card slot.
Turn on your Sam460.
When prompted to do so by the firmware, press enter on the keyboard to activate the boot selection menu.
When the boot selection menu appears, press enter again to activate the boot device menu. From this menu choose 'USB HD'.
Press enter to confirm your choice in the boot device menu, then escape and enter again to select 'boot this configuration'.
MorphOS will now start booting. Once it is done booting, follow the on-screen instructions.