I'm not sure those changes will really help - are you sure it works reliably after applying them?
Even if USB is broken, you could always connect to the USB connector you used to flash and everything would be fine. I think it's unlikely it is broken though as it's the same chip as the Espruino Board - and those lines were changed intentionally as the USB wasn't reliable (and interrupted every msec) with them in.
jswrap_object_hasOwnProperty won't be used at all unless it is explicitly called, and your changes break it anyway.
Espruino is a JavaScript interpreter for low-power Microcontrollers. This site is both a support community for Espruino and a place to share what you are working on.
I'm not sure those changes will really help - are you sure it works reliably after applying them?
jswrap_object_hasOwnProperty
won't be used at all unless it is explicitly called, and your changes break it anyway.