@cesur
I was able to replicate this issue with the info you shared. Looks like the emulated_devices_module.js file does not exists. I tried directly downloading the file and got a 404. This is a bug in gapdebug as before starting the debugger it parses the device specific chrome dev tools appcache manifest and attempts to download all files. In this case it should ignore the 404 and complete the download process rather than just quit. Unfortunately we are no longer developing GapDebug. You can learn more here.