Official HTC ROM updates are released as RUU (ROM Update Utility), which you run on your (Windows) PC to get the target device updated automatically.
Some of the big brains in the Android community release RUUs re-packaged into signed update files,
which in turn allow for whatever ROM customization you can imagine.
In this how to I will explain how to extract ROM files from a RUU image,
which you can then customize and use to flash your device without the fear of a new bootloader possibly making your device unrootable.
Microsoft Process Monitor,
File Archiver capable of extracting ZIP files(eg, 7ZIP),
Official HTC RUU for your Android device.
The process of extracting ROM files from a RUU is really straightforward.
The idea behind it is that the self-contained update utility first needs to unpack the update payload into a temporary folder before pushing it onto the device.
This is when we grab the ROM file...
1. download the official RUU
2. start Process Monitor.
3. press CTRL+L
4. change "Architecture" to "Process Name"
5. leave the "is" field as it is
6. in the empty field copy and paste the name of your
RUU file (eg, RUU_Ace_Sense30_S_HTC_WWE_3.12.405.1_Radio_12.65.6 0.29_26.14.04.28_M_release_225512_signed.exe)
7. click "Add"
8. change "Process Name" to "Path"
9. change "is" to "Contains"
10. in the blank field type "rom.zip" (without quotes)
11. click add
Click "OK" to set the filter and then run the RUU file.
Once the utility starts switch back to Process Monitor and look for an entry in the "Path" column that ends with "\rom.zip".
Right click on that line and select "Jump to..."
this will open a Windows Explorer window in the folder which contains the zipped ROM files
Copy the "rom.zip" file to some other folder, outside of the temp RUU folder tree (eg, desktop)
Once copied, close Process Monitor and the RUU utility.
The copied "rom.zip" file contains the following files:
android-info.txt - list of CIDs this RUU will flash to,
boot.img - root file system image,
hboot (followed by a version string) - boot-loader update,
radio.img - radio driver update,
recovery.img - recovery partition image,
splash1_Hero_320x480.nb0 - boot loader splash image,
system_rel.img - system partition image,
userdata.img - data partition image.
You can now, among many other things, root the ROM
and then flash the updated boot.img and all the other image files on to your device using Recovery