Do I have to install Ubuntu on my computer for S-OFF ?
since you have 1.27 hboot version if you want to flash only rom then S-OFF is not necessary for youNo... just tell on this thread or other thread for s-off what os you computer have and ask for that version of juopuntbear
Example this thread http://forum.xda-developers.com/showthread.php?t=1614617
and surely you have 3.32 or 3.33 firmware version(depending from your hboot version)
just post the output of the command
fastboot getvar all
remove imei and serial number