Originally identified by XDA memeber fardjad the HBOOT partition on the Runnymede is not protected and can be written to with a rooted phone. Due to some limitations in that procedure, Unlimited.IO created HBOOTS which provide more complete S-OFF functionality as well as optionally providing overwrite protection.
This page contains modifed HBOOTS for the HTC Sensation XL (runnymede). These HBOOTS provide S-OFF and limited Engineering HBOOT behaviour for the HTC Runnymede. The HBOOTS enable flashing of radios and also ROMs from any region (SuperCID).
The protected HBOOTS have built in protection that prevent them from being overwritten by an RUU or a stock HBOOT. If you wish to return to stock or flash a stock HBOOT for some other reason you must first flash the unprotected HBOOT.
Runnymede S-OFF HBOOTS currently support the following Android devices:
HTC Sensation XL (Runnymede)
To load the first of these HBOOTS on your phone if you are on a HTC factory HBOOT you must be rooted, either by using a temporary root such as zergRush, tacoroot or sparkyroot or by performing the bootloader unlock and flashing superuser. Installation is then performed using the following procedure:
sudo ./adb push hboot_7230ddr2_Runnymede_6.25.4444.nb0 /data/local/tmp
sudo ./adb shell
# dd if=/data/local/tmp/hboot_7230ddr2_Runnymede_6.25.4444.nb0 of=/dev/block/mmcblk0p18
sudo ./adb reboot-bootloader
If any of the HBOOTS from this page or the HBOOT from jardjsudo ./adb's original thread have been previously flashed then it is not necessary to follow the above procedure, instead the new HBOOT can be flashed directly using fastboot using the follow command:
fastboot flash hboot hboot_name.nb0
fastboot flash hboot hboot_7230ddr2_Runnymede_6.25.4444.nb0
Support for Runnymede S-OFF HBOOTS is on IRC channel #unlimited on freenode. If you do not have an IRC client you can use the link below.