Imac pro A1862 switch off after apple logo and half progress bar

[sajidmirza]

Hi,
I got a iMac pro A1862 820-00967 in dead conditions, restored in apple configurator successfuly.installed macOS Catalina from internet recovery successfully but after installation it boots with apple logo way to the half of progress bar and shuts down.replugged 2 ssd's of 512GB and cleaned all the RAMs.Still not completely booting.tried PRAM reset but lo luck.Can any one guide me what should I do next.

[reformatt]

Catalina is too old most likely for the BridgeOS that's installed. You should use Shift-Option-Command-R, not CMD + R for recovery. That should install a later version of MAC OS (like Monterey). You can't change the startup security to boot off USB till you have the OS installed and created an Admin account.

I wonder what will happen to all these T2 systems when Apple decide to shut down their end for recovery. I setup all T2 systems to enable boot from USB.

[sajidmirza]

Catalina is too old most likely for the BridgeOS that's installed. You should use Shift-Option-Command-R, not CMD + R for recovery. That should install a later version of MAC OS (like Monterey). You can't change the startup security to boot off USB till you have the OS installed and created an Admin account.

I wonder what will happen to all these T2 systems when Apple decide to shut down their end for recovery. I setup all T2 systems to enable boot from USB.

yeah i have done that too,now its sonoma but still behaves same.reballed T2 chip but of no change
Thanks though