samsung / Reset, Flash & Recovery

Samsung Galaxy S21

Official reset & flash steps, plus guided recovery if something goes wrong — every download clearly marked official or third-party.

Select your exact model variant first

Flashing firmware meant for a different region/carrier variant can cause serious issues (IMEI/baseband loss). Confirm your model code in Settings > About phone.

Reset & Flash Steps

Pick what you want to do.

1 minute
No data loss
Steps
  1. 1 Press and hold Volume Down + Power button for about 10 seconds until the device restarts.

Something Went Wrong?

Tap what you're seeing to get the fix.

Device-Specific Warnings

Button combo
Download Mode: Volume Down + Volume Up held together while connecting the USB cable.

The S21 has multiple model codes (SM-G991B global/Exynos, SM-G991U US carrier-locked, SM-G991U1 US unlocked) with different basebands. Flashing the wrong one can cause IMEI/signal loss, not just a simple brick. Always confirm your exact model code before downloading any firmware.

  • Flashing global (Exynos) firmware onto a Snapdragon US unit will hard-brick the device.
  • Interrupting an Odin flash mid-process (disconnecting cable, losing power) can corrupt the bootloader.

All Downloads for This Device

Every file and tool used above, in one place.