Hi Rex_alex,
Yes, it is interrupted in the middle of downloading process.
Yes I’m.
Yes, I think so, and the modem now trapped in infinite loop. 
I’m using DWLWIN V.4.1.6.16 (directly download from sierra wireless download page), but it doesn’t work as expected, it always error (see image below), with status message “Boot failure: failed to install the downloader in memory, Failed to boot up the remote target”
Do you think I must use special cable to “play” with boot pin & reset pin?
Please explain where I can get wiring diagram about how to create special cable, because explanation in AirPrime New Q24 Series Customer Design Guideline.pdf confusing me
Thanks.
[attachment=0]dwlwin.PNG[/attachment]