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MP 1,1-5,1 Mac pro 4,1 Single CPU will only boot with either 1 or 2 sticks of original 1gb Hynix Ram.

GreppMichaels

macrumors member
Original poster
Apr 17, 2020
50
10
Los Angeles, CA
Recently acquired a "non-working" 4,1 single cpu mac pro that came originally configured with 16gb of Kingston ram. The computer wouldn't chime or post video. Spent a ton of trouble shooting every part and was able to get it running with either ONE or TWO sticks of 1gb Hynix from my old 4,1. It wouldn't boot with any other ram sizes or configurations, including from another working single CPU tray. There are NO red error LED's, I've done the reset button on the motherboard near the battery, i've reset the NVRam/PRam (whatever it is when you hold in P and R) and when I run the top left diagnostic LED I get the green and yellow right under (from my understanding of the service manual that's what I want to see).

I'm currently reinstalling the OS and will then perform a firmware update to 5,1 to see if maybe that makes any difference, again it doesn't seem to matter what I do regarding the CPU tray, my concern is if this is a backpane/logic board issue, which is the only sense I can make of it. Anyone have any other insight?

EDIT

I am unable to update the firmware, so maybe there is something deeper that's wrong here, I've updated on two previous 4,1's. In this case, I have SIP disabled, follow all steps, when it gets at the screen to begin the process it shows the progress bar for a second and then immediately powers off. I've tried it several different times and re-downloaded, and same error, including confirming SIP is disabled. Turns out I have a B08 Firmware on here, apparently I need to reconstruct my bootrom, no idea how.
 
Last edited:

Lunarcruiser

macrumors newbie
Oct 31, 2020
1
0
Recently acquired a "non-working" 4,1 single cpu mac pro that came originally configured with 16gb of Kingston ram. The computer wouldn't chime or post video. Spent a ton of trouble shooting every part and was able to get it running with either ONE or TWO sticks of 1gb Hynix from my old 4,1. It wouldn't boot with any other ram sizes or configurations, including from another working single CPU tray. There are NO red error LED's, I've done the reset button on the motherboard near the battery, i've reset the NVRam/PRam (whatever it is when you hold in P and R) and when I run the top left diagnostic LED I get the green and yellow right under (from my understanding of the service manual that's what I want to see).

I'm currently reinstalling the OS and will then perform a firmware update to 5,1 to see if maybe that makes any difference, again it doesn't seem to matter what I do regarding the CPU tray, my concern is if this is a backpane/logic board issue, which is the only sense I can make of it. Anyone have any other insight?

EDIT

I am unable to update the firmware, so maybe there is something deeper that's wrong here, I've updated on two previous 4,1's. In this case, I have SIP disabled, follow all steps, when it gets at the screen to begin the process it shows the progress bar for a second and then immediately powers off. I've tried it several different times and re-downloaded, and same error, including confirming SIP is disabled. Turns out I have a B08 Firmware on here, apparently I need to reconstruct my bootrom, no idea how.
Michael, I don't know if this will solve your whole problem... but I came across only today The Technicians Guide to early 2009 mac pro...here's the url (good luck):http://tim.id.au/laptops/apple/macpro/macpro_early2009.pdf
 
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