Fix BLU004 on Samsung Galaxy M21 & M21s
Error Code
BLU004
Affected Devices
M21 & M21s
Resolution Time
5-15 minutes
System crash
Power off your device completely, wait 30 seconds, then power it back on. This resolves most temporary software glitches affecting the M21 and M21s.
Go to Settings > About Phone > Software Update. The M21 and M21s benefit significantly from firmware updates that address error codes and improve stability.
Power off, then hold Volume Up + Power + Bixby buttons simultaneously until the Samsung logo appears. Select "Wipe Cache Partition" using volume keys. This is especially helpful for M21 and M21s devices experiencing persistent errors.
Go to Settings > Apps. Uninstall or disable apps installed recently before the error appeared. Third-party apps can sometimes conflict with M21 and M21s system processes.
Ensure your M21 or M21s has at least 2GB of free storage. Low storage can trigger error codes and affect performance on these devices.
If the error persists, back up your data and go to Settings > General Management > Reset > Factory Data Reset. This completely resets your M21 or M21s to factory settings.
If none of these steps resolve the issue on your M21 or M21s, contact Samsung support directly for hardware diagnostics and assistance.
Both models feature a 6.4-inch AMOLED display with 60Hz refresh rate. If you're experiencing display-related errors, these steps address common software issues affecting the M21 and M21s screens.
The M21 and M21s come with a 6000 mAh battery with 15W fast charging. Battery-related errors may stem from power management software conflicts specific to these models.
The M21 and M21s are powered by a Samsung Exynos 9611 processor with 4GB/6GB RAM options. System errors on these models often relate to RAM optimization or processor thermal management.
Both models feature a triple rear camera setup (48MP main, 8MP ultra-wide, 5MP telephoto). Camera-related error codes on the M21 and M21s typically resolve with cache clearing or app reinstallation.
Restart device
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