SOLVED WITH POST #4. GO TO SOLUTION...
My situation is :
I have a HTC One S [ S4 ] with unlocked bootloader and S -OFF . So for the reason I could install a new ROM , I had done a HBOOT version update (which I do not think is official, I am also not so well informed ) , namely , version 2.16 ( previously I had 2.15).
I've installed a modified version of TWRP that works on this HBOOT version .
Now I had this Stock Based Rom ( I do not remember exactly the name) installed and am one day to the function " Encrypt ... " encountered ! I did that and it works flawlessly.
After some time I wanted to install a different ROM ... I started up with recovery and TWRP asks me for my encryption password ! Okay I give the 4 numbers ... WRONG !
Although it is the judge Password certainly does not take TWRP to the PW . When I click Cancel , I do come into TWRP but can not do anything ! No flashing possible! I know to "undo" the encryption a reset is necessary , okay but I cannot flash anything
Can I reformat all partitions and therefore can install a new ROM?
RUU is no alternative since there is no version for this HBOOT . I hope someone can help me , the phone is indeed only the ROM does not run that great and that's why I 'm not so happy with the current function .
I hope that I can install another ROM or the Stock ROM.