Resolved Flashed 5,1 2009 MP, need help Reinstalling OS

[nick7caz]

Sorry if this has been discussed. Recently acquired a 2009 MP 4,1>5,1 with RX 580. I can see the os image from the bootcamp viewer, but it wont boot into macos Catalina. It will just re boot into windows. I may have deleted the macos boot from the image, but not sure. Holding option brings nothing up, and neither does command r, it will eventually just go to a black screen with a blinking line.
Keeping windows isn't paramount, I just need MacOS back up. I have also tried usb bootable with Mojave, and left it in with nothing but a blank drive, and it will just give me a screen saying "Please insert bootable disk".
Appreciate any help.

 

[permanentmacdabbler]

I can see the os image from the bootcamp viewer, but it wont boot into macos Catalina. It will just re boot into windows. I may have deleted the macos boot from the image, but not sure. Holding option brings nothing up, and neither does command r, it will eventually just go to a black screen with a blinking line.

Do you know if Catalina is a dosdude1 or similar patched install? Catalina can’t be officially booted or installed natively on a 4,1/5,1 so if it is appearing on a drive I don’t think it would boot via the methods you described.

If the patched part is missing or damaged you may need to reinstall/patch again or it may be easier to remove all drives and install a fresh supported OS such as Mojave or High Sierra instead then when you’re setup try access the files on the old macOS volumes again.

Can you remove the Windows drive and see what boots without it? I am not sure if it’s on a separate drive or partition but if Windows is currently blessed or is the only OS available it may explain why you are struggling to boot recovery or do anything macOS related.

Edit: Do you have a boot screen capable GPU? If not you won’t have any ability to use the alt boot manager to select any OS but it should show a booted standard macOS USB installer if it is the only thing in the device.

 

[nick7caz]

Do you know if Catalina is a dosdude1 or similar patched install? Catalina can’t be officially booted or installed natively on a 4,1/5,1 so if it is appearing on a drive I don’t think it would boot via the methods you described.

If the patched part is missing or damaged you may need to reinstall/patch again or it may be easier to remove all drives and install a fresh supported OS such as Mojave or High Sierra instead then when you’re setup try access the files on the old macOS volumes again.

Can you remove the Windows drive and see what boots without it? I am not sure if it’s on a separate drive or partition but if Windows is currently blessed or is the only OS available it may explain why you are struggling to boot recovery or do anything macOS related.

Edit: Do you have a boot screen capable GPU? If not you won’t have any ability to use the alt boot manager to select any OS but it should show a booted standard macOS USB installer if it is the only thing in the device.

Appreciate you taking a look.
Not sure how, but I got it working again. Windows is on a separate hard drive. I made a time machine back up on a empty ssd I had from my MBP running Catalina. Once that was done, I attached the ssd with a usb to sata cable and opened boot camp in Windows. There were the Windows, and MacOs there plus the new SSD I had just made. I restarted and it booted right into my old Catalina partition. Before I did anything, I reinstalled Catalina with the dosdude1 patcher and took the ssd out of the usb cable. So far no issues. I know now that my RX 580 doesn't allow me to see the boot screen. When I had created a USB bootable drive, it would just run to a blank screen with a flashing underscore.
Again, thanks for taking a look at this. I find the whole issue was strange.