Develco WISZB-120 and SMSZB-120 Firmware Update process FAILURE

[Krzysztonek]

Since June 2025 I have been regularily notified by Z2M add-on that each of my Develco WISZB-120 and SMSZB-120 devices need to be updated with a new firmware version:

Unfortunately, when trying to start updating the firmware of any of the mentioned devices, the process either:

• is being interrupted after few/dozen percent of completion, never reaches its end, each attemp ends with a failure

OR:

• doesn't start at all

I don't understand what am I doing wrong.. or it might be a bug somewhere in the update process code.. May I count on your kind support, please?