How to Fix Lenovo K8 Plus Baseband Unknown and IMEI Invalid

Android users will sometimes run into the problem of their baseband reporting “Unknown” status, or the IMEI reporting as “Invalid”. This typically happens in several scenarios:

  • Dirty flashing your stock ROM.
  • Installing third-party ROMs on untested device.
  • Your device suddenly deciding to be a pain.

What basically happens is that the EFS folder which contains your device’s IMEI number somehow becomes corrupted. When this happens, your Android device will display the following symptoms:

  • The Bluetooth address is unavailable
  • WIFI connection will work inconsistently
  • Constantly rebooting
  • Fake IMEI or Null IMEI # (normally – 004999010640000)
  • Null Serial number -(0000000)
  • Unable to register to network

Because different device brands have different methods of fixing this, the guide we are giving here is for the Lenovo K8 Plus only. Please do not attempt to follow this guide with any other Android device.

Please be aware that part of this guide involves unlocking your bootloader and rooting your device towards the end of the steps. Unlocking your bootloader will wipe all of your user data and reset your device to factory settings. Make sure you backup all of your important data before proceeding!

Also see: How to Unlock and Root the Lenovo K8 Plus with TWRP and Magisk


  1. The first step is to download the Lenovo K8 Plus stock firmware and SP Flashtool from the download link above, and extract them on your desktop.
  2. Next install the SP Flashtool, and the ADB drivers (these are USB drivers specific to the Lenovo K8 Plus).
  3. Check exactly which firmware version your Lenovo K8 Plus is running in Settings > About Phone > Firmware, and write it down for later.
  4. Now enable USB Debugging on your Lenovo K8 Plus by going into Settings > About Phone > tap on ‘Build Number’ 7 times until Developer Mode is activated. Next go to Settings > Developer Options > Enable USB Debugging.
  5. Launch the SP Flashtool on your computer, and in the button for loading a scatter file, browse to the Lenovo K8 Plus stock firmware folder and choose the scatter.txt file.
  6. Shut down your Lenovo K8 Plus, and click the Download button in SP Flashtool, then immediately connect your Lenovo K8 Plus to your PC via USB – this will automatically begin the flash process.
  7. Once it has successfully flashed the scatter file, reboot your device.
  8. Once the Android system has booted up, power off your device again, disconnect it from the USB, and repeat the above process, but use the scatter.txt file from the Firmware/LK folder.
  9. After it has flashed, when you reboot your Lenovo K8 Plus, it should bring you to the Bootloader Mode.
  10. Now run the HWFlash.bat in the firmware folder for your device version, for example “firmware/Programutags_XT1902-1_AP_Dual_SIM”.
  11. Power down your Lenovo K8 Plus once more, and again load the scatter file from the firmware folder, but uncheck all of the options in SP Flashtool except Pre-Loader and LK.
  12. After you flash the scatter file once more, you should have your baseband returned when you power on your Lenovo K8 plus.
  13. To get your IMEI back, you are going to need to unlock your bootloader and root your Lenovo K8 Plus using TWRP and Magisk. Please follow Appual’s guide “How to Root the Lenovo K8 Plus with TWRP and Magisk” if you have never done this process before.
  14. Once your Lenovo K8 Plus has been unlocked and rooted, you need to download ToolHero.apk onto your device and launch it.
  15. In the ToolHero menu, hit the button “IMEI” and then put in your device’s original IMEI number – this can typically be found underneath your battery, if you don’t know it.
  16. Once you reboot your Lenovo K8 Plus, your IMEI should be returned to its original state!
Kevin Arrows
Kevin is a dynamic and self-motivated information technology professional, with a Thorough knowledge of all facets pertaining to network infrastructure design, implementation and administration. Superior record of delivering simultaneous large-scale mission critical projects on time and under budget.
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