Dual SIM roaming issue on one SIM card after updating to One UI 8.5

Peamishoack50

Hello,

I am experiencing a severe network issue on my Samsung device following the recent update to One UI 8.5. I am using a Dual SIM configuration, and since the update, the roaming service on one of my SIM cards has completely stopped working.

The problematic SIM card shows “No Service” or fails to register on any foreign network while abroad.

What I have already tried (without success):

Enabling/disabling 2G/3G compatibility modes.

Manually searching and selecting a network operator.

Turning Data Roaming off and back on.

Resetting Network Settings.

Booting the device in Safe Mode.

Clearing the SIM Toolkit app cache and data.

Wiping the system cache partition via Recovery Mode.

It seems like a deeper modem/firmware bug introduced in One UI 8.5 that breaks roaming profiles for specific SIM slots or dual-SIM setups. Has anyone found a workaround, or is there an upcoming hotfix for this Baseband issue?

Daniele_Sunrise

Peamishoack50 Welcome to the community!

Have you been able to resolve your issue in the meantime?

Greetings
Daniele

Peamishoack50

Daniele_Sunrise

I managed to fix the issue, and it turned out to be a coincidence with the system update—the root cause was actually on the carrier’s side (Sunrise). There was an incorrect configuration parameter set on their end for this specific phone number that blocked the connection.

To find this out, I had to call their customer support from a different phone number. Because of the long weekend, I couldn’t reach them sooner, but they finally sorted it out and fixed the parameter yesterday. The SIM card is now logging into the roaming network perfectly.