3G support is completely orthogonal to anything custom.
I have no idea how the 3G deprecation is progressing, but the PW1 is EOL, and its final FW version is 5.6.1.1, so, you can try updating, but that's it.
Just make sure you've installed a recent Hotfix (i.e., snapshots), and you should be safe.
No idea if it'll actually help with 3G *at all*, though (again, device EOL, and service being deprecated)

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