I'm in the same boat.
Originally Posted by scruff72
I fixed it....your advice got me to digging and I actually formatted the partition and then was able to load CM11. Thanks again...greatly appreciated.
Hi, I'm in a similar situation with my newly acquired HTC One M8.
I have access to bootloader and recovery (TWRP v.188.8.131.52), but I'm getting all the same "failed to mount ***" errors as you were having.
Can you please elaborate on how to "format the partition" or point me to a detailed thread/article on how to do that?
And any notes on how you got it back to work are very appreciated - I've spent hours and hours researching a trying things without any success.
I'm sorry I'm somewhat new to this...
Let me know if you need any more info and thank you for your help in advance.