Subject: 5G Modem Failure After Bootloader Unlock - SM-A066B

[elyeandre]

Dear Samsung Support Team,

I am writing to report a serious issue with my Samsung Galaxy A06 5G (SM-A066B) where the 5G modem has permanently failed after unlocking the bootloader using Samsung's official procedure.

DEVICE DETAILS:

Model: SM-A066B (Galaxy A06 5G)

Baseband: A066BXXS2AYD3

Original Firmware: A066BXXS2AYD3

One UI Version: 7.0

Purchase Date: August 25. 2025

Device Condition: Brand new when issue occurred

WHAT HAPPENED:

I followed Samsung's official bootloader unlock procedure on my new device. After unlocking the bootloader and attempting to boot a custom kernel (built from Samsung's own open source code), the 5G connectivity completely stopped working.

ISSUE SUMMARY:

After unlocking the bootloader and attempting to boot a custom kernel (built using Samsung’s official open-source code), the following issues began and have persisted even after restoring to stock firmware:

1. Complete 5G Failure:

• No 5G network access at all
• Only 2G/3G/4G connectivity remains functional
• This persists even after relocking the bootloader and flashing stock firmware

2. SIM Instability & Periodic Signal Loss:

• The device loses all network signal every 6 hours, requiring a full reboot to reconnect
• SIM card frequently disconnects and reconnects in cycles
• This issue occurs even with different SIM cards and carriers

3. Other Symptoms Observed:

• Unusual heating during network activity
• Performance degradation and increased battery drain
• Signal instability despite using official firmware and stock kernel

ATTEMPTED FIXES:

I tried everything to restore functionality:

- Flashed back to official stock firmware using Odin

- Successfully re-locked the bootloader

- Factory reset multiple times

- Tried different firmware versions

The bootloader now shows "Official" status and everything appears normal, but the 5G modem remains permanently broken. All other network functions work fine (2G/3G/4G), but 5G is completely non-functional.

THE PROBLEM:

This appears to be a hardware-level failure that occurs during the bootloader unlock process or when booting unsigned firmware. Even though I restored everything back to official Samsung firmware, the 5G capability cannot be recovered.

This means:

- Samsung's own bootloader unlock procedure may cause permanent hardware damage

- A device marketed as "5G capable" loses this core feature permanently

- The phone essentially becomes equivalent to the 4G-only A06 model (SM-A065F)

IMPACT ON USERS:

This is concerning because:

- Users lose a major advertised feature permanently

- There are no warnings about potential permanent damage

- It affects the device's value and usability

- Multiple users in developer communities report the same issue

WHAT I'M REQUESTING:

1. Investigation into why this hardware damage occurs

2. A solution to restore 5G functionality on affected devices

3. A firmware update to prevent this from happening to other users

4. Clear documentation about risks involved in bootloader modifications

I followed all official Samsung procedures and used Samsung's own source code, yet still experienced permanent hardware failure. This seems like a serious quality control issue that needs attention.

Please let me know if you need any additional information or if there are any solutions available.

Thank you for your time and assistance.