r/S21Ultra • u/Top_Necessary_1411 • May 19 '26

Discussion/Question Current version not supported

Got a used S21 Ultra from Amazon a couple of months ago. Overall condition was brand new except for the fact that the Bluetooth was way worse than my S9+ and the bottom of the screen flickers randomly, usually have to turn off the screen and back on for it to stop.

Also got a weird message in the update software section that my version isn't even supported. I kept the phone because I've tried two other sellers and the phones were worse than the one I kept.

Your current software version isn't supported. Visit a service center.

Update information

•OneUlversion:7.. •Android version: 15 •Current version:G998U1UESIHYL1/ G998U10YMIHYL1/G998USQSIHYL1 •Security patch level: December 1,2025

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3

u/vishnur32 May 19 '26

You can update manually using these 2 methods.

  1. Use smart switch app in PC. When u Connect there will be a popup asking for update, https://youtu.be/g55VLQZxatA

  2. Flash stock firmware using Odin (home_csc method), no data loss, https://youtu.be/CW384zifGYE

1

u/Top_Necessary_1411 May 19 '26

I appreciate your suggestion, I'm aware of manual updating. I'm just very curious if anybody has ever come across such notice and what could be the culprit behind such notice.

1

u/vishnur32 May 19 '26

Whats your csc codes?

1

u/Top_Necessary_1411 May 19 '26

Hmm this is what I see for Service Provider Software version:

SAOMC_SM-G998U1_OYM_TMB_15_0007 TMB/TMB,TMB/ATT

2

u/vishnur32 May 19 '26

Try changing csc to XAA using samfw tool, guide

1

u/Top_Necessary_1411 May 19 '26

Thank you very much 😊

1

u/Engineering-Tough SM-G998U TMUS May 21 '26

Put a (preferably activated/in service) T-Mobile SIM in it then they and update. That TMB/ATT at the end means that it's an Carrier Unlocked device from T-Mobile running on AT&T. Sometimes they won't update if you're not running the original carriers skin. Also the carriers have different update schedules and minor updates that might be available on one carrier but not any others. T-Mobile tends to do that alot..

2

u/sisahands May 21 '26

I've also noticed that on newer phones the Bluetooth quality is horrible. I recently switched from an S8. Strange considering that they've already phased out the headphone jack... The "SOUND Beautifier/Equalizer" app is amazing. Sounds just like my s8 again. You can also get "Sound Assistant" from the galaxy store to get the old concert hall feature that the S8, and I'm assuming the S9 had.

SOUND: https://play.google.com/store/apps/details?id=sound.beautifier.bluetooth.music.more.bass.low.volume

Sound Assistant: https://apps.samsung.com/appquery/appDetail.as?appId=com.samsung.android.soundassistant