A couple of days ago, HTC rolled out the Sense 5.5 with Android 4.3 update for the international variant of the One. The update also included free 25GB of storage space on Google Drive for 2 years. Sadly, this promotional offer is not valid for Ones with unlocked bootloader or the developer edition. 

Fear not, as the developers over XDA forums have found a workaround to this problem. The process is slightly tedious and requires the use of ADB/Fastboot, but should be worth it for the free 25GB of storage space that you get in the end.

Step 1: Assuming you have ADB/Fastboot setup on your PC, you will first need to reset the lock status flag on your One. For this, connect your One to the PC with USB Debugging enabled. Type in the following command and make sure that your device is being detected by ADB -:

adb devices

Step 2: If your device has been detected, proceed to enter the following commands one by one -:

adb devices

adb shell

su

echo -ne ‘\x00\x00\x00\x00’ | dd of=/dev/block/mmcblk0p3 bs=1 seek=33796

exit

exit

Make sure to enter the commands one by one, and after a gap of 3 to 5 seconds.

Step 3: If you have followed and entered the commands properly, you should have successfully managed to lock the bootloader of your One. Disconnect your device from the PC and reboot it once. Now, open up the Drive app and then proceed to reclaim the 25GB of storage space offer.

If you end up getting a Device ID error, make sure to use a custom ROM that is closer to stock. The above step will work with Custom ROMs like Android Revolution HD or  Maximus HD. It has been reported to not work on InsertCoin, Eragon and other similar ROMs.

If you want to re-unlock your bootloader, you will need to enter the following commands -:

adb devices

adb shell

su (if needed to get a # prompt)

echo -ne “HTCU” | dd of=/dev/block/mmcblk0p3 bs=1 seek=33796

exit

exit

adb reboot bootloader

The above steps will not wipe your internal storage, so there is no need to worry about your data. Keep in mind that the above steps work only if your One has already been unlocked and rooted. If you are looking to unlock and root your One for the first time, follow this guide.

If the bootloader of your HTC One is locked, you simply need to open the Google Drive app to redeem the free space.

Credits to scotty1223 for his hard work!