I'm curious... How are you able to get the Inovelli firmware link? I have tried a few times to get the link to their latest firmware (1.17 for the Red series switch) but all I seem to be able to do is to download it...
That said, I see you added the link, so will use it!
I saw this app for Windows 10 from Windows store, Simple http server. Pretty straight forward for setting up. The otz and hex file can be save locally then just paste the generated address into the firmware updater app.
Any ideas on what's mismatched? Am I using the right FW? I'm not sure what the difference is between the HEX (on the github) and the HEC (I found in Z-FLash), though I'll assume the 'c' stands for compressed or something?
Prior to clicking the "Update Firmware" button, I've been rebooting the dimmer using the air gap. Everything seems to work right up to the point of uploading the firmware to the switch. The below screenshot shows the end state of the update attempt.
Below is a screenshot of the log containing the entire update attempt.