Just a quick video in case someone else has the same issue, this is what I did to get my bricked Sena SMH10 back from the dead.
Long story short, the latest version of the software would not work for my Sena SMH10 but the older version did. Here's a copy of it since I couldn't find it on the Sena website.
00:00 - Intro
00:16 - What caused the issue
01:19 - The core issue
02:00 - The fix
03:18 - Summarise
03:28 - Other things to try