mobile

HI! Today I got an HTC Sensation from a friend and it was laggy due to it's stock rom with preinstalled apps and stuff, so I decided to move to a custom ROM, the first one which caught my eye was 5.0 CM12 from the development section, so I copied it to sdcard.
I have managed to unlock the bootloader through the htcdev site and then flashed the lasted CWM Recovery available, 5.8.0 and then formatted cache, data, system, dalvik, because that's what I've always been doing on my Galaxy S2, it was very straight forward.
But now, I can't install a custom rom, tried that one and the slim pyramid one, even a cyanogenmod rom but still no luck. It would abort the installation and output an error about filesystems which can't be found or it woudn't say nothing but will restart the phone straight to recovery mode.
Also, tried 4ext recovery and still no luck. At this point I started panicking and tried to resolve this by installing the stock rom, RUU.
Downloaded RUU_PYRAMID_ICS_HTC_Europe_3.33.401.53_Radio_11.76 A.3504.00U_11.24A.3504.31_M_release_280871_signed , which is the perfect match for my phone but also fails to finish installation, telling me something about failed/unknown mounts/filesystem... If it will help, I will tell you exactly what the error is.
At this moment I have S-On in bootloader, and can't see any radio serial metioned at the top. Tried some instructions flashing PG58IMG.zip , but it doesn't seem to do anything.

Please, help me out because at this point my phone won't go anywhere but bootloader and recovery.