I gave that a try earlier.

Attempts
1. Used your method
Result: despite the main drive set as the next to boot it boots the CD instead.

2. Boot install cd, let timer run out and used: rd=disk3s2 -v
Result:
Panic(CPU 0 caller 0x002D8B62):"nfs_boot_init failed with 6\n"@/Volumes/disk1s2/leo_xnu/xnu-1228/bsd/nfs/nfs_vfsops.c:851
*then some debug stuff and it hangs with my kernel version. Actually it said kernel 9.2.0 im assuming from the install disk. Though the install disk isnt really active during boot.
Something else I noticed is in the PAnic it lists disk1s2 which is my backup drive. disk3s2 is my main install.

3. Boot install cd, let timer run out and used: rd=disk3s2 -v -f -F -legacy
Result:
Hangs at "Still waiting for root device"

4. Same as 3 but added -x
Result:
Same as 3

Im having a noob moment.

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