Ashton1

macrumors newbie
Original poster
Jul 15, 2018
25
6
Chicago, IL
Hi,
I have a flashed (4,1 to 5,1) Mac Pro that was running Mojave with no problems until....I decided to give it to a friend and erased the HD and seem to have erased the OS too!!
I have tried to make a bootable installer on a USB stick (which seemed to go fine) except when I hold down the option key or try the Option +R key I never get the restore screen...just blank screen..

The info is as follows:
Mac Pro (2009), Radeon RX580 8Gb graphics card, 120Gb SSD, and it was previously running OS 10.14.6 (Mojave).

Any suggestions for how I can get (any) OS re installed on this..?
Thanks,

Alan.
 

Wernerempire

macrumors newbie
Dec 21, 2015
4
0
Vancouver, BC
Hi, sorry if this advice is obsolete:
only use the build in USB or FireWire ports.

Remake the USB installer on a different media, or on FireWire.

Lastly: Boot the cMP into Target mode and connect it to your other Mac, preferably in Mojave. Use Carbon Copy Cloner to clone a Mojave Recovery partition onto the cMP, boot from that.

Very lastly: use a different, older graphics card
 

thielsa

macrumors newbie
Dec 30, 2006
29
21
Your video card doesn't support you seeing the boot select screen. It is there but you can't see it. If you have the original card put it in and you should be able to proceed. The only other thing I can think to try is to side click and guess until you hit on the usb. Somewhat of a stab in the dark.
 

h9826790

macrumors P6
Apr 3, 2014
15,267
7,559
Hong Kong
Hi,
I have a flashed (4,1 to 5,1) Mac Pro that was running Mojave with no problems until....I decided to give it to a friend and erased the HD and seem to have erased the OS too!!
I have tried to make a bootable installer on a USB stick (which seemed to go fine) except when I hold down the option key or try the Option +R key I never get the restore screen...just blank screen..

The info is as follows:
Mac Pro (2009), Radeon RX580 8Gb graphics card, 120Gb SSD, and it was previously running OS 10.14.6 (Mojave).

Any suggestions for how I can get (any) OS re installed on this..?
Thanks,

Alan.
Wrong hotkey.

You better select your USB installer from system preferences -> startup disk.
 

eyoungren

macrumors Core
Aug 31, 2011
23,450
17,066
ten-zero-eleven-zero-zero by zero-two
Your video card doesn't support you seeing the boot select screen. It is there but you can't see it. If you have the original card put it in and you should be able to proceed. The only other thing I can think to try is to side click and guess until you hit on the usb. Somewhat of a stab in the dark.
Is it possible that in OP's erasing the HD and wiping the OS that OP also wiped the recovery partition?
[automerge]1595960227[/automerge]
Wrong hotkey.

You better select your USB installer from system preferences -> startup disk.
If OP wiped the drive and that removed the OS, how do they do what you suggest?
 

Wernerempire

macrumors newbie
Dec 21, 2015
4
0
Vancouver, BC
If OP wiped the drive and that removed the OS, how do they do what you suggest?
You definitely wiped the Recovery and everything.
Target Disk mode is the solution.
Boot the cMP into Target.
Attach any Mac in Mojave.
Easiest, now boot the attached Mac into Recovery, chose Install, select the Target disk - and you're done.
=====
Edit: Addition:
- If you cannot boot into Target mode, because you don't have FireWire cables - take the hard drive out, put it into a USB box, attach that to a Mojave running computer, do all the updates on that disk, before you put it back into the cMP, done!
 

h9826790

macrumors P6
Apr 3, 2014
15,267
7,559
Hong Kong
Is it possible that in OP's erasing the HD and wiping the OS that OP also wiped the recovery partition?
[automerge]1595960227[/automerge]

If OP wiped the drive and that removed the OS, how do they do what you suggest?
I don't know how can he erase the boot driver inside the OS. May be he means "damaged" the OS, therefore, can't boot to OS anymore.

If that's the case, the recovery partition should be still there. And hold Command + R to boot to recovery partition should work.

To OP, I am a bit confused what you've done. But if you never format the drive, the recovery partition should be still there. For RX580, make sure only one monitor is connected (preferable display port connection), hold Command + R to boot (NOT option + R), then wait for a few minutes. Depends on your drive, it can cause quite a few minutes before you can see anything on the screen.
 
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Ashton1

macrumors newbie
Original poster
Jul 15, 2018
25
6
Chicago, IL
Thanks everyone for the replies....
The solution that worked for me was swapping out the RX580 for the original graphics card and then I installed High Sierra. I'm confused as to why I couldn't do this with the RX580 since the machine was already running with Mojave and that graphics card before I tried to erase the HD before giving it away.
At one point when I was trying to reinstall Mojave I got to transferring it to the Mac Pro from the USB stick but a message came up saying something like "your graphics card doesn't support metal" etc. and there was no way to proceed with the upgrade...that's why i just put High Sierra on it and my friend can upgrade to Mojave later if he wants.
Thanks again for the suggestions.
Alan.
 
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