Pepijn BruienneMoreover, it appears that TMo are using the #Fibocom FG360-NA-03 specifically as seen in aforementioned datasheet. The difference with the FG360-NA-00 and FG360-NA-05 versions is that their datasheet lists "driver" as “Linux 4.1” instead of OpenWRT for the -03 spec. Main difference between all of them seems to be supported wireless bands as they apply to the carrier. The -03 variety for TMo appears to support a bunch more bands (TMo + Sprint) as a result. The #MT6890 AP is a #CortexA55, for completeness sake.
What, you thought I wasn't going to self-nerdsnipe? So according to TMo's datasheet[1] the gateway contains a #Fibocom #FG360NA 5G module which itself is built on the #Mediatek #T750 SoC, which (yes it's turtles all the way down) contains a number other MT ICs including an #MT6890 quad-core ARM AP. That processor apparently is running a "driver" designated as “Kernel 4.19 #OpenWRT 19.07 (?)” but according to the previous research it boots Android? Weird stuff.
Wish me luck while I decide whether to attempt soldering headers onto the alleged UART connection of the 5G gateway I am supposed to return unharmed to its rightful owner, eventually 🧯
[1] https://www.t-mobile.com/content/dam/tfb/pdf/tfb-iot/FIBOCOM%20FG360-NA-03%20Datasheet_V1.6.pdf