Original topic:

A55 OTA Problem

(Topic created: 09-02-2025 05:25 AM)
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fiqxtys
Constellation
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A Series & Other Mobile

Hello I have A556E device after rooting , and going back to stock rom (relocking the bootloader , flashing the latest fw from odin) I'm getting error as "Connecting to server" , "Registration Failed" is there anyway to fix this

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wasifali758595
Cosmic Ray
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A Series & Other Mobile

When you root and then return your Samsung A556E to stock ROM, errors like โ€œConnecting to serverโ€ or โ€œRegistration Failedโ€ usually mean the device isnโ€™t fully restored to a clean, factory state. Even though you flashed the latest firmware with Odin and re-locked the bootloader, some remnants of the root process or mismatches in firmware (CSC, modem/baseband, or region settings) can prevent the phone from connecting to carrier servers.

โœจThink of it like rebuilding a house: even if the walls look freshly painted (the stock ROM), if the wiring underneath (modem, CSC, bootloader state) isnโ€™t aligned perfectly, the lights wonโ€™t turn on.

Here are a few key steps you can try:

  1. Check the Firmware Package โ€“ Make sure you flashed the full 4/5-file firmware (BL, AP, CP, CSC, HOME_CSC) from your exact deviceโ€™s region. Using the wrong CSC or partial package can break carrier registration.

  2. Use CSC instead of HOME_CSC โ€“ Flashing with CSC (not HOME_CSC) will wipe the device completely and reset carrier/network configs, which often resolves registration issues.

  3. Verify IMEI/Network โ€“ Dial *#06# to confirm your IMEI is intact. If it shows null or โ€œunknown,โ€ rooting may have corrupted the EFS partition, which stores network identity. In that case, restoring EFS from a backup or professional repair service may be required.

  4. Factory Reset After Flash โ€“ Once you re-flash, boot into recovery and perform a manual factory reset. This clears any leftover data conflicts.

  5. Carrier/Region Lock โ€“ Ensure the phone isnโ€™t region-locked or carrier-locked; if it is, you may need the original SIM or an unlock code.

If all else fails, itโ€™s best to re-flash the exact official firmware for your region from a trusted source like SamMobile or Frija and carefully redo the process. If the IMEI/EFS is intact, this usually brings the phone back to normal.

In short: the error means your device isnโ€™t talking properly with carrier servers because of mismatched firmware or corrupted network data โ€” a clean, region-matched flash with CSC (plus checking IMEI) is the most beautiful way back to stability.

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fiqxtys
Constellation
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A Series & Other Mobile

Hello thank you for your reply I see the IMEI and there isn't problem also before returning to stock I have used Frija tool to retrieve the stock rom I'm using an app to check my CSC there doesn't seem to be a problem should I factory reset through recovery? 

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