How to perform system upgrade using 3G instead of WiFi? I use my android device as my home internet service - for the most part it works ok with occasional dropouts which was a known issue with my phone (Moto G 2nd gen 4.4.4) so was pleased to find out there is a new update available (5.?.?).

Problem is my phone refuses to do the upgrade until I connect it to a Wifi network - and since its a 300+ MB download the local McDonalds free wifi isn't gonna cut it (i'm in Melbourne, Australia and were pretty stingy with our public wifi)!

Is there a way to bypass this idiotic restriction? I have plenty of GB available to download via 3G, also is this an android thing in general or specific to this model?
You can always sideload the upgrade. So download it over your 3G into a folder and then sideload it. You can download directly from google and you can find instructions on sideloading for your phone/os all over the web.