@user1995565 Thanks for the update. (16) If (a) Your setup works on Mode 2 for Google SUPL server, but not for Mode 3, and (b) The other couple of users in rpi.org.forum also reported the same experience, I then to think that it is the SIM7600 firmware that is buggy. (17) There is a big possibility that even you use Neo-8M, as I suggested, you might also have the same "Only Mode 2, but not Mode 3" problem, because it might also related to the Google SUPL server in you geological region.

(18) uBox Neo-8M has a similar thing called "Assisted GNSS (A-GNSS)". I did not dig deep into the details of the Neo-8M google A-GNSS assist server, so I am sorry that my very superficial knowledge won't help in your troubleshooting.

(19) In case you finally give up troubleshooting in you current WaveShare SIM7600 approach, and would consider using a not too cheap Amazon/AliExpress uBox Neo-8/9M module to compare and contrast with SIM7600 to hopefully to get some insight of what goes wrong, I am giving two references to help starting off.

(21) In the long term, I am interested to see if WaveShare will be producing a new version of SIM7600, say SIM8600/9600 etc for 5G, at a similar price, then I might consider going back the SIM way.

(22) So I am stalling here. Good luck and hope to join you guys later. Cheers.

@tlfong01 No worries, and thanks for your thoughts! I agree that it does sound like either a firmware issue or a SUPL server problem. If you happen to know of any other SUPL servers I could try, that would be greatly appreciated! For what it's worth, I have two SIM7600 modules. One has older firmware (SIM7600A-H) and the other, with the newest I believe (SIM7600G). Interestingly enough, UE-based mode 2 works on the older one, but not the newer.

Your hardware alternative suggestions are interesting though. For background, my goal is this: a device that supports CAT4 LTE (not NB-IoT or CAT-M1), supports A-GPS or A-GNSS (so it can work indoors relatively well and fast) and is as small as possible. So if you know of any good A-GPS/A-GNSS very small breakout boards for the above-suggested modules or any other modules, that would be super helpful! I would actually prefer getting results not via AT commands, honestly. It's far cleaner. :)

Or, if there is an alternative where it uses AT commands and combines LTE CAT4 or whatever with A-GNSS/A-GPS as a very small breakout board footprint (40mm * 40mm or smaller), that would be awesome! Thanks for your help so far!

CAT1*, doesn't need to be CAT4