Petter Reinholdtsen

Unlocking HTC Desire HD on Linux using unruu and fastboot
7th July 2016

Yesterday, I tried to unlock a HTC Desire HD phone, and it proved to be a slight challenge. Here is the recipe if I ever need to do it again. It all started by me wanting to try the recipe to set up an hardened Android installation from the Tor project blog on a device I had access to. It is a old mobile phone with a broken microphone The initial idea had been to just install CyanogenMod on it, but did not quite find time to start on it until a few days ago.

The unlock process is supposed to be simple: (1) Boot into the boot loader (press volume down and power at the same time), (2) select 'fastboot' before (3) connecting the device via USB to a Linux machine, (4) request the device identifier token by running 'fastboot oem get_identifier_token', (5) request the device unlocking key using the HTC developer web site and unlock the phone using the key file emailed to you.

Unfortunately, this only work fi you have hboot version 2.00.0029 or newer, and the device I was working on had 2.00.0027. This apparently can be easily fixed by downloading a Windows program and running it on your Windows machine, if you accept the terms Microsoft require you to accept to use Windows - which I do not. So I had to come up with a different approach. I got a lot of help from AndyCap on #nuug, and would not have been able to get this working without him.

First I needed to extract the hboot firmware from the windows binary for HTC Desire HD downloaded as 'the RUU' from HTC. For this there is is a github project named unruu using libunshield. The unshield tool did not recognise the file format, but unruu worked and extracted, containing the new hboot firmware and a text file describing which devices it would work for.

Next, I needed to get the new firmware into the device. For this I followed some instructions available from, and ran these commands as root on a Linux machine with Debian testing:

adb reboot-bootloader
fastboot oem rebootRUU
fastboot flash zip
fastboot flash zip
fastboot reboot

The flash command apparently need to be done twice to take effect, as the first is just preparations and the second one do the flashing. The adb command is just to get to the boot loader menu, so turning the device on while holding volume down and the power button should work too.

With the new hboot version in place I could start following the instructions on the HTC developer web site. I got the device token like this:

fastboot oem get_identifier_token 2>&1 | sed 's/(bootloader) //'

And once I got the unlock code via email, I could use it like this:

fastboot flash unlocktoken Unlock_code.bin

And with that final step in place, the phone was unlocked and I could start stuffing the software of my own choosing into the device. So far I only inserted a replacement recovery image to wipe the phone before I start. We will see what happen next. Perhaps I should install Debian on it. :)

Tags: bootsystem, debian, english, opphavsrett, sikkerhet.

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