I got further away this time I think.
The drive is added to the icdfmt.dat file, in correct form, drive zeroed, power off, jumper changed to 1.3, boot up the icd install disk.
Run ICD's format tool, detects drive properly, all set up right. Name: HardDrive, Partition: DH0, flagged FFS and BOOT.
Select Partition, program does it's job and installs workbench 1.3.
Exit program. HardDrive appears on workbench.
remove floppy, replace with install 2.1.
Reboot, hold mousebuttons.
Drive is in boot menu.
Booting to drive causes terminal guru errors if it's using workbench 1.3.
Booting to DF0: with Install 2.1 works well, HardDrive is visible on workbench. Try to us Install 2.1 tool and it gurus.
Whereas booting to workbench 2.1 and then doing a straight copy of everything seems to work. But I can't make it boot properly then, it'll have a fit at the Startup-Sequence and hang in AmigaDOS.
After that I can manually loadwb endcli and it's fine.
If I add icdmount to User-Startup on workbench 2.1 and boot from DF0:, the drive mounts perfectly and is usable.
I'm ready to kill the designer of this thing.