i had a same problem and used the startup like in OS4, here it is:
----
Assign t: RAM:
Version exec.library VERSION 38 >NIL:
If WARN
assign SYS: dh0:AmigaOS/wb2.1/
CD SYS:
assign FONTS: fonts
assign L: l
assign LIBS: libs
assign DEVS: devs
assign C: c
assign S: s
Else
assign SYS: dh0:AmigaOS/wb3.1/
CD SYS:
assign FONTS: fonts
assign L: l
assign LIBS: libs
assign DEVS: devs
assign C: c
assign S: s
EndIf
execute s:startup-sequence
quit
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my root on dh0 partition contains only few directories (amigaos, c, s) and used commands are from wb2.1; for some reason, Zacs solution didnt work directly.
