During the course of testing alternative adapters for the Mini (more on that later)
found that there may be at least two different Interconnect boards in the Minis.
After failure getting a newly formatted and OS 9.2.2 - installed SSD to boot
(using the top board ©2004 - pictured below) pulled the SSD and then with
an RXD adapter newly attached, placed into a Quicksilver and
it booted the QS!
Afterwards noticed the differences between these two Interconnect boards.
While the top board has more contacts merged / joined (even three more sets
of them on the backside). Changed SSD and new test adapter back to the ©2005
Interconnect board and the Mini then booted without issue.
Backside pic:
https://www.ebay.com.au/itm/Apple-Mac-Mini-G4-Interconnect-Board-820-1660-A-2004-/264483865489So, if you’re having difficulties booting a Mini after the OS 9.2.2 install, you may
want to check to see if you’ve got this 2004 Interconnect board and just how many
of the contacts may be merged / joined. Assume that this is the case with the very
early G4 Mini’s and especially the 1.25 GHz models.
(References note: in 1.42 GHz models too.)
Apple part numbers:
630-6581 and 630-7099 / 820-1660-A and 820-1838-A

*clickable image