How can I wipe an encrypted device? My HTC One (M8) is a little soft-bricked being that the drive is encrypted. 
I can't factory reset in CWM recovery because it says

formatting /sd-ext
E: Unknown volume for path /sd-ext
Formatting /sdcard/.android_secure
Error mounting /sdcard/.android_secure
skipping format
formatting /storage/sdcard1/.android_secure
Data wipe complete
press any key to continue


I can flash ROMs but my Hboot is 3.16 and I have S-ON. Since firewater is discontinued I can't use that to S-OFF and update.

I have a feeling that my options are to get a Lollipop ROM and then unencrypt (KK uses password not pattern) or have to wipe the device some how.

I do have a custom recovery installed, and the device is rooted.
So, to do this I went to the mounts and storage and used the format /data and /system option. Apparently the other options by themselves (/data and /system) do a different thing. I have a feeling this rebuilt my partition table.

As Izzy suggested I had a look at manually formatting it but it seems that that route is a little short-lived. I'd reccomend for anyone reading this to make sure they try the /sdcard format on the recovery.

in CWM is has these options format /data format /cache and one that says format /data and /data/media (/sdcard) the latter works the former doesn't.