how to remove custom MTD partition : Uninstalling: Removing this is simple. Boot in to fastboot Fastboot flash the original unmodified clockwork img Reboot into recovery Format system, data, cache Install ROM/ZIP, gapps etc, reboot
Will my phone stay S-OFF forever?
Yes and no. As soon as you decide to flash a stock RUU that has a HBOOT update in it, this hacked HBOOT will be overwritten.