I think the CID-change will do you good. I tried for several hours to get the OTA-applied, however, only after I changed my CID from 11111111 to "HTC__001" the update finally applied. Before that I only got "assert failed". What's strange:
In the updater-script the CID "11111111" is "regarded" in theory, however, it did not work for me! Maybe there's a bug in the code like Apple's "Goto fail"-bug?
For everyone having issues with the Sense6-OTA: CHANGE YOUR CID TO "HTC__001" (thats two underscores __, CID is always 8-digit). Took me really several hours, I found it strange that I didn't see this anywhere mentioned.