I got 2 US Version Nexus 5, on my 12G, Singtel Value (Equivalent) plan SIM, plug into phone..work out of box.
Another Singtel SIM, on the obsolete classic plan + 1 GB data. during setup, which took long time to activate the mobile plan, then skipping the step. after full setup ( including OTA patching of new FW). After setup complete, the phone could not connect to 3G..it just connected without data.
Plugging the same SIM(Classic plan) back to Nexus 4, data/vioce works perfectly..
Pulling my hair..dont know what went wrong, calling Singtel..there are trying to reset the line for me..keeping finger crossed on whether resetting the line will make it work. I just want normal 3G to work
Trying another M1 3G mobile broadband SIM..it works out of box as well.