[Tutorial] Update to hboot 2.15 via RUU

Running an RUU is only simple for those who haven't been messing with their devices, and that usually isn't us. Since I just did this, I want to write down the steps because I was not able to find easy answers.

This assumes your device is rooted with a different ROM installed. If that is not the case, then you can just download and run the RUU for your device, end of instructions.

Downloading the correct RUU
The most complete list of RUUs for Ville is found on androidruu.com
T-Mobile: http://www.androidruu.com/getdownloa...gned_ICS_2.exe
HTC Europe: http://www.androidruu.com/getdownloa...signed_2_4.exe
There are RUU updates listed for other service providers, but I can't tell if they are JellyBean hboot 2.15 or not. If someone knows, I'll update this post.
Preparing your device

Make your device s-off if it isn't already. Why?

1. You will not have to relock the bootloader to perform the RUU update.
2. You will not have to flash the boot image separately.

If for some reason you can't or won't go s-off, you can still do this, but will have many more steps to follow.
Instructions to make your device s-off are here for firmwares below 3.14: Facepalm S-Off for HTC Devices One S, One XL, Droid DNA
Or you can use the HTC All-In-One Toolkit which helps you through the process.

Use the HTC All-In-One Toolkit (link above) to change the CID to match the RUU.
You needed Super CID to gain s-off, but it won't help you install RUUs. Even if you are Super CID (11111111), you must change your CID to match the RUU you are installing (mine is TMobile: T-MOB010). I know, kinda defeats the purpose of being Super CID, but the RUU won't succeed otherwise. If you are s-off, it is a one click operation using the All-In-One Toolkit.

Backup your device
Use Titanium backup to backup all your user apps so you can restore them afterwards. (No, don't restore system apps please!)
Also back up your ROM by booting into recovery mode and selecting Backup.
If you are only updating the hboot but keeping the same ROM, you can just restore the backup afterwards. Not sure why anyone would need to update the hboot without installing a new ROM, but then you also have a backup in case things go wrong.

Run the RUU
If you are s-on you will have to relock the bootloader by rebooting into the fastboot mode, connecting your device to the computer and running the command "fastboot oem lock". You will also have to follow the process again to unlock your bootloader after doing the update. Tutorials for that are found elsewhere.

1. Leave bootloader unlocked, and leave s-off as is. No need to go back to s-on or relock bootloader.
2. Run the RUU and wait while it updates the phone (Incidentally, it didn't even wipe my sd partition data!)
3. While you are still in bootloader mode (before booting up), use the All-In-One tool to install the TWRP S4 recovery. Or, if you don't want to use the tool, you'll have to download a recovery and use "fastboot flash recovery" followed by the name of the recovery img file.
4. Reboot bootloader and enter recovery mode
5. Restore from backup or Mount USB from TWRP and copy over the ROM and gapps package, flash, wipe cache, and you are up and running.
If you are s-on you will need to extract the boot.img from the zip you are flashing and flash that image separately with "fastboot flash boot boot.img"

Note that device still has the unlocked bootloader and is still s-off!

My device before: hboot 1.09, unlocked bootloader, Super CID, s-off (In layman's terms, this is a device with an unlocked bootloader so it can accept other ROMs, set to accept any service provider's RUU update via SuperCID, and has had write permission to the boot sector removed via s-off).

My device after: hboot 2.15, unlocked bootloader, T-MOB010 CID, s-off

If possible, I will answer your comments or questions by updating this post and I'll refer you back to here.