Having trouble updating Moto G3's to Android 6.0

[FTC9899]

We have several Moto G3 phones that are all running (or will be running) Android 5.1.1 out of the box. We are trying to update them to Android 6.0 to comply with rule <RS03> in Game Manual Part I. They are (or can be) connected to a WiFi network. The phones are not getting update notifications, nor can they manually check for an update (no button to tap). Is flashing an official Marshmallow factory image my only option, or am I missing something?

Thanks,
FTC9899

Here are links to some screenshots of where the update option should be, but isn't:

https://drive.google.com/open?id=0B86sInPWYDgMdGszaGFsNUxCRzRoTVV1c0dfMmpWR2ZCWXRz

https://drive.google.com/open?id=0B86sInPWYDgMOEhqRktCWXBZaFJQYVZWbkh4YUFZSEY4cWZ3

https://drive.google.com/open?id=0B86sInPWYDgMNXlCV3V6eEpfd1VaS0ZGR1k2NkJYaEhxRW5R

[FTC9899]

Maybe this is because the Marshmallow update for my specific device (XT1548) has not happened yet. Can anyone confirm this, or does anyone have Marshmallow on their XT1548 Moto G 3rd generation?

Thanks,
FTC9899

[dmssargent]

Maybe this is because the Marshmallow update for my specific device (XT1548) has not happened yet. Can anyone confirm this, or does anyone have Marshmallow on their XT1548 Moto G 3rd generation?

Thanks,
FTC9899

As far as I know the following document can be used to upgrade the phones to Marshmallow (US Cellular ROM) https://drive.google.com/file/d/0B1d...hmZV9ac0E/view (credit to original post by maths222).

[mhaeberli]

The Moto G 3rd generation comes in at least _two_ different US model numbers: XT1540 and XT1548.
We now own a bunch of Sprint-branded, nominally unlocked, XT1548, which at version 5.1.1.
I will try the above update procedure on one of them, but would recommend that First specify Moto G 3rd gen models that are known to be upgradeable to 6.0 or above (if they don't ship that way).
Thanks,
Martin Haeberli
(de-)Mentor, FTC 7593, TigerBots

[mhaeberli]

After more investigation, it appears that:
XT1548 US Cellular can be upgraded to 6.0+, for example, as shown by dmssargent.
XT1548 Sprint can not (based on my tests just now).
If anyone has guidance otherwise (besides rooting the phone and using Cyanogenomod, which seems kind of besides the point), please advise.
Thanks,
Martin Haeberli
(de-)Mentor, FTC 7593, TigerBots

[mhaeberli]

I succeeded at converting a "Sprint" XT1548 to a "US Cellular" XT1548 running Marshmallow.
Just had to follow the instructions VERY carefully.
Thanks,
Martin Haeberli
(de-)Mentor, FTC 7593, TigerBots

[mhaeberli]

Looks like it will work - it's a bit of a Frankenstein monster in that the baseband is still reporting "Sprint".
Thanks,
Martin Haeberli
(de-)Mentor, FTC 7593, TigerBots