@Avery.2PiFi seems it is also reported at the other thread (MAX BR1 Mini HW3 Cellular firmware issues and questions - #3 by Avery.2PiFi).
The module firmware was introduced recently, and the firmware update via the <support.cgi> page will be supported in the upcoming firmware (tentatively 8.5.2).
Meanwhile, you can load this special firmware (8.5.1s079) and it will allows you to perform the firmware update (tested working, shown below).
