Use the firmware in the link I provided, but follow the instructions from the link you are using for the altboot.
The trouble would seem to be that when you updated initially to an 073 release, you did not get notified of this
This release uses OpenSSL version 1.0.2h
WARNING for WC3655 / WC 6655 upgrades only: Once the system is upgraded to this SPAR Release it cannot be downgraded to the GM
release 072.060.034.16800/072.110.044.20500 or SPAR R14-11 release 072.060.134.32804/072.110.134.32804.
You cannot go backwards using any method to an 072 release.
to disable data backup, add a file (blank) with no extension and name it DISABLE_DATA_BACKUP to the folder on the USB key with the firmware DLM