Hello together,
I’m using a Chateau 5G (D53G-5HacD2HnD) and my Modem Firmware is currently on RG502QEAAAR11A06M4G.
The error happened first while using latest stable 7.11.2 but also persists with 7.12rc1.
Firmware upgrade check shows the RG502QEAAAR13A03M4G would be available:

However when i try to upgrade the firmware the following error occurs almost immediately:

Does anyone had this error before and was able to find a solution?
Reboot, Power Cycle or USB Power reset didn’t helped so far…