[One (M8) Q&A, Help & Troubleshooting] EddyOS:
OK, going by that ID we can assume it's an EU unbranded handset. Or we can at least we can treat it as such. So, assuming you want to go back to 100% stock Sense (but keep S-OFF) do the following:

First, download the following to your fastboot folder:

4.16.401.10 RUU ZIP - https://drive.google.com/file/d/0B17smFr95pleU2NqcVB3NWxoNnM/view (rename it ruu.zip - not ruu.zip.zip)

htc_fastboot.exe - https://www.androidfilehost.com/?fid=95897840722646249

1.54.401.5 FW ZIP - http://www.androidfilehost.com/?fid=23329332407589439 (rename it firmware.zip)

TWRP - http://techerrata.com/file/twrp2/m8/openrecovery-twrp-2.8.4.0-m8.img (rename it to recovery.img)

HTC Sync Manager (for the drivers) - http://www.htc.com/uk/support/software/htc-sync-manager.aspx (install it and then uninstall Sync Manager but leave the drivers)

1. First things first, change the CID to Super CID - fastboot oem writecid 11111111

2. Once done, reboot the bootloader to confirm it's showing the Super CID - fastboot reboot-bootloader

3. Once confirmed it's set, we now need to set the right MID in case this was changed by the seller. To do this, we can use TWRP. Flash TWRP (downloaded earlier) - fastboot flash recovery recovery.img

4. Once flashed, boot into TWRP and connect the phone to your PC

5. Once the drivers are installed, make sure the PC sees the phone by typing adb devices

6. So long as it's been shown as a connected device, type adb shell

7. We can now change the MID to the EU unbranded one by using the following command (copy/paste this as it has to be exact)

echo -ne '\x30\x00\x50\x00\x36\x00\x42\x00\x31\x00\x30\x00\x30\x00\x30\x00\x30' | dd of=/dev/block/mmcblk0p5 bs=1 seek=16384

8. Once done, we can now 'lock' the bootloader using the following command (whilst still in adb shell)

echo -ne '\x00\x00\x00\x00' | dd of=/dev/block/mmcblk0p2 bs=1 seek=33796

9. And we can also reset the tamper flag at the same time

echo -ne '\x00' | dd of=/dev/block/mmcblk0p6 bs=1 seek=5314564

10. Once all that is done, type exit to leave adb shell and then reboot the phone into the bootloader through the reboot menu in TWRP

11. Once back at the bootloader, you should find the phone is now 'LOCKED' and it shouldn't say 'TAMPERED' at the top either but should still have the black bootloader interface that the GPe has. We can now set it all back to Sense

12. Reboot the phone into RUU mode - fastboot oem rebootRUU

13. Once in RUU mode, flash the firmware ZIP - fastboot flash zip firmware.zip

14. The process will fail the first time and reboot. Run the same command again once it's rebooted - fastboot flash zip firmware.zip

15. Once finished, reboot the phone to the bootloader to confirm you now have the white 'Sense' bootloader - fastboot reboot-bootloader

16. Assuming it's correctly flashed, reboot back into RUU mode - fastboot oem rebootRUU

17. We can now flash the RUU using the htc_fastboot package - htc_fastboot flash zip ruu.zip

18. Once finished, reboot back to the bootloader one last time - fastboot reboot-bootloader

19. Once back in the bootloader, change the CID to HTC__001 - fastboot oem writecid HTC__001

20. Reboot the bootloader to confirm the change has been successful - fastboot reboot-bootloader

21. Once back at the boot loader, disconnect the phone and boot into recovery and do a factory reset

22. Once the reset finishes, reboot the phone

That should get it all working but any issues obviously let us know