Latest update (Dec19) broke Mobile network access on S20 and N20 Ultra (Unlocked, Canada)

[Artemus]

So my friend and myself are in a weird situation. We are on two different carrier and both have Samsung 20 series devices, an S20 and a Note20 Ultra. Both got the same update and after reboot neither of us could connect to the mobile networks.

Here is what we tried:

- Confirmed APN was correct (all good, even grabs the right APN on sim swap)

- Swap sim card between 3 carriers who use different bands

- 911 still works but only without a SIM installed, install a SIM it's dead completely.

- Factory reset via OneUI as well as Bootloader

- Odin Flash to previous version, working fine

- Odin Flash to current version, no Mobile network access.

Add this on top of the random reboots we were both getting on Android 12 for about 6 months, we're both tired of this. We went from a minor inconvenience of a reboot 1-3 times a week to not being able to use our phone outside of Wifi and not be able to use the phone as a phone.

Has this occurred to anybody else? He's ready to jump ship, I'm considering it as this should not have happened, not something so major, on two different devices, who are both unlocked and on different carriers.

Thanks,

A

[AndrewL]

@Artemus: If you have already completed a factory data reset, and the issue has persisted, then you may wish to reach out to your network to request a SIM swap to see if this helps. Also, head to Settings > Connections > mobile networks > Network operators, and toggle on 'Select automatically' if applicable. Tap the back button > SIM card manager, and make sure that your SIM is toggled on, and is assigned to Calls and Messages in the 'Preferred SIM card' section below. 

[Hot_Chilli]

Yup. Samsung suggest a new Motherboard after factory resets and flash resets failed.

[IbnSams]

I'm having a similar issue? a new motherboard??! Any idea on what  whats the best way to get that done?

[Hot_Chilli]

Samsung should cover it if it's caused by a software update. I think this stands even if it's outside the warranty period under Trading Standards. Go to your nearest store.

I've had to get a new phone as Samsung wouldn't honour the warranty due to a cracked screen, they weren't will to carry out the motherboard works they proposed and quoted £250. So they will pretty much do everything to avoid fixing it. But good luck!