2018 Mac Mini eGPU boot screen with Catalina - Boot ROM update

[mavots]

I understand that running a display via an eGPU disconnects the boot screen in MacOS's prior to Catalina (Mojave, etc).
With Catalina, the update apparently installs a new Boot ROM that allows normal boot screen operations while running a monitor through an eGPU.

I don't want to install Catalina just yet (32-bit apps). Is it possible to start the Catalina update and allow it to update the Boot ROM and then not proceed with the actual update? I used to do this on my cMP 5,1. I pressed the power button during install and a buzzer went off telling me the new Boot ROM was flashing. Optical CD trays opened and closed, it was all very dramatic!

So I'm asking if the same procedure (w/out an optical drive!) would work with a Catalina install. Or is the whole OS update procedure different now?

 

[ibarnett]

Thank you for your question.......
I have upgraded to Catalina & had only been using onboard iGPU because of the comments in Catalina thread:

Catalina & eGPU...

How is eGPU working with the latest beta?

forums.macrumors.com

Having just read your question above I thought well, why not try.
Result was no problems at all, plus what seems to be a full normal boot screen, took a little while to appear but I had Apple Logo plus full progress bars 😀
My system:
Mac mini 2018, 3 Ghz 6-Core i5
64 GB 2667 Mhz DDR4
Razer Core X T3
Saphire Nitro+ Radeon RX580 8 Gb
Samsung 49" LC49J890

 

[D.T.]

Wow, this is pretty awesome news for eGPU setups!

 

[mavots]

Thank you for your question.......
I have upgraded to Catalina & had only been using onboard iGPU because of the comments in Catalina thread:

Catalina & eGPU...

How is eGPU working with the latest beta?

forums.macrumors.com

Having just read your question above I thought well, why not try.
Result was no problems at all, plus what seems to be a full normal boot screen, took a little while to appear but I had Apple Logo plus full progress bars 😀
My system:
Mac mini 2018, 3 Ghz 6-Core i5
64 GB 2667 Mhz DDR4
Razer Core X T3
Saphire Nitro+ Radeon RX580 8 Gb
Samsung 49" LC49J890

That's great!
Just to be clear, you were able to install the Catalina Boot ROM and still use Mojave. And the eGPU/Radeon RX580 boots into Mojave with the full boot screen?
Was there a clear point where the Catalina installer lets you flash the Boot ROM and then get out before the OS installs?

 

[Sun Baked]

Also looks like my USB-C SSD is reporting correctly now, with 900 mA available and using 896mA. Instead of the old 500mA available.

 

[Queru]

Just wait, don‘t upgrade. Let Apple fix issues they created with 10.15. Castalina made my Mac mini with egpu unusable in macOS. Read about the issues I encountered in this thread: https://forums.macrumors.com/threads/catalina-bricked-my-mac-mini.2204752/
And just wait with update until they fix it

 

[mavots]

Just wait, don‘t upgrade. Let Apple fix issues they created with 10.15. Castalina made my Mac mini with egpu unusable in macOS. Read about the issues I encountered in this thread: https://forums.macrumors.com/threads/catalina-bricked-my-mac-mini.2204752/
And just wait with update until they fix it

Thanks, I have absolutely no intention to upgrade to Catalina until my 32-bit apps are upgraded to 64-bit. Also, I usually wait until about a .3 to .4 update is dropped before upgrading MacOS's any more!