A53. SIM card slot 1 doesn't work after update

[Sman42]

I updated my phone recently, and got One UI 6. And after that SIM card slot 1 stops working.

If a sim card is installed in slot 1 then there is no service, even if the phone is showing E (Egde) and signal level in the notification area. And I checked SIM status, it is showing "connecting".

If I install the same sim card to slot 2 then everything works fine!

I went to carrier office and we tried a few different sim cards there, got same result for all sim cards: nothing works in slot 1 and slot 2 works fine.

Again, it happened after the update, so this is definitely a software bug. 

Very very frustrated and disappointed. Samsung Mobile division and QA - this is terrible! 

[Loyd Koon]

Call your carrier and make sure mobile data provisioning didn't get turned off by the carrier. After that, have them push an update to the phone for the correct APN. Tho two items are mainly the issue.

[Sman42]

Please read my post. I visited the carrier office and they tried different things. 

This is not because of the carrier. APN is correct.

SIM is working in slot 2 and doesn't work in slot 1. This happened after a software update.

[Loyd Koon]

I did read your post. I had a dual Sim a71 that was globally unlocked and had this too happen. The problem is the update package was incorrect for your phone. Go to samfrew.com and look up the exact BUILD Number for your phone. You find that in settings/about phone/software. It should have a string of numbers and letters ending with a three letter country code. Download the latest .zip for your device and find on xda-developers website a modified Odin package. You will then have to flash your .zip to your phone while in download mode.

There are guides on xda to do this properly.

[Loyd Koon]

And to be honest with you nobody that is Samsung employed will ever tell you this. You can also download Samsung own SmartSwitch utility to your pc and do an emergency software flash which will also fix it

[Sman42]

So you are suggesting updating firmware manually. I'm pretty familiar with that stuff and I know how to do that. How about other people? If they follow your advice there is a very high chance to brick their phones.

This is not what I expected when I bought the phone - to update firmware manually. 

[Loyd Koon]

Not using smart switch. It's direct from Samsung for your specific device once you plug it in to the pc. Now a Patched version of Odin can brick it only if you flash the wrong stuff to it. Use smart switch if you are uncomfortable

[userX846XC]

It's definitely caused by the update. Since the update, my phone freezes and crashes many times per day, has trouble staying connected to the network, and MMS messages won't go through unless I turn wifi off. Nothing has changed on my phone except the last two updates... or rather downgrades. Samsung tech support has no solution other than, "Did you report it?" Sooo not helpful samsung. Could you please send an update that puts everything back to the way it was 2 weeks ago? Life was so much better then.

[Sman42]

Agree. Samsung support is terrible. Always saying that this is a carrier problem. It can't be a carrier problem because SIM card is working in slot 2 and it is working in another phone. Any other SIM card doesn't work in slot 1 on my phone.

Samsung QA is useless - they are making locked phones for carriers and are unable to properly test the firmware/update.

[Loyd Koon]

Once you get the update technically you need to do a factory reset after the phone gets finished. This makes sure there isn't any left over junk from the previous version causing conflicts.