Do I have to use the mobile network with the standard ROM before installing GOS?

Moschatus

As I recall, I read at the time regarding the OnePlus 5 that you had to be logged into the mobile network at least once with the stock ROM before installing another ROM in order for VoLTE to work (in some countries).

Is there any reason why this is also necessary for GrapheneOS on Pixels?

When I was in Austria, roaming didn't work. After much searching, I discovered that the Pixel 8a with GrapheneOS was missing the APN values for the roaming partners. Could this problem be due to the fact that I installed GrapheneOS without first using the stock ROM?

DeletedUser495

Moschatus as far as I recall the only two reasons why you need to connect your phone to network prior to flashing GrapheneOS is to confirm OEM unlock and update your device to latest Android version.

r_dac

The Pixel 10 Pro I purchased had OEM Unlocking greyed out until I connected it to WiFi. It did not need a SIM card installed and it did not need to connect to Cellular at all to enable OEM Unlocking - just connection to the internet via WiFi.

n3t_admin

r_dac I think that's besides the point. OP is asking if it needs to connect to cellular for VoLTE to work in GrapheneOS.

I believe no? Although I am not sure about different providers. It doesn't sound very logical why you would need to connect to VoLTE on the stock OS.

NetRunner88

You do not need to connect to mobile network with the base OS. GrapheneOS work out of the box with VoWifi or VoLTE depending on your provider support

Moschatus

I only mentioned VoLTE on Oneplus 5 as an example of how it can make a difference if a device was once registered with the stock ROM.
As I said, my actual problem with GrapheneOS on the Pixel 8a is that data for the APNs is missing. I have now started a new discussion on this topic with a more appropriate title.
Thank you all.