[Motorola Droid 4] Sjaakbanaan:
1) This is getting interesting.. that would be 31440 (314 = USA, but does not seem to be used yet). Adding an APN with this ID in telephony.db does not seem to work however, it does not show up (even after reboot). I tried adding 2 APNs, one with the 'numeric' set to 31440 and the MCC/MNC at 204/04, and another one in which MCC/MNC are also update to 314/40.

2) Yes, I've changed the settings where needed. Most settings didn't seem to have any effect, except for the SMS routing (which prevented me from sending any messages). More specifically, I've been tampering with these settings in the build.prop, current values shown:

telephony.lteOnCdmaDevice=0

ro.mot.phonemode.vzw4gphone=0

ro.mot.eri=0

ro.cdma.nbpcd=1

ro.mot.phonemode.vzwglobalphone=0

ro.telephone.gsm-routes-us-smsc=0

ro.cdma.home.operator.isnan=0

keyguard.no_require_sim=true

gsm.sim.mot.simswap=0

ro.telephony.default_network=10 (should be 7?)

3) Running on the original Moto .215 leak: 6.16.215.XT864.Verizon.en.US

4) This is what I tried before, but to no avail.

When I put in another SIM card, I get a different error ('This SIM card is from an unknown source.' rather than 'not supported').

I decided to try running logcat immediately after boot, just before I get the SIM error message, and do this for both SIM cards. Using a diff tool was nearly impossible, so I compared them manually.

Since I have no idea how to visualize it here, let me try to summarize:

The "D/HuxSncTransactionService( 2133): onDestroy" occurs before the SIM information in the Vodafone logging, but after the SIM information in the Telfort logging. That could indicate some kind of terminated process due to ..

Vodafone logging shows:

D/SetupPhoneService( 652): Received simState = LOADED
D/SetupPhoneService( 652): SIM Card state READY
D/SetupPhoneService( 652): SIM operator = 20404
D/SetupPhoneService( 652): SIM type APPTYPE_USIM
D/SetupPhoneService( 652): Not a 4G SIM

Telfort logging shows:

D/SetupPhoneService( 653): Received simState = LOADED
D/SetupPhoneService( 653): SIM Card state READY
D/SetupPhoneService( 653): SIM operator = 20412
D/SetupPhoneService( 653): MCC_MNC for SIM type APPTYPE_SIM is null
D/SetupPhoneService( 653): Unknown SIM operator

(note that Telfort has no 4G, and is using another provider's network which also doesn't offer 4G yet)

Edit: Note the subtle difference between APPTYPE_SIM and APPTYPE_USIM. Not sure what this means, both SIMs are UMTS/HSDPA capable.

Telfort SIM again/still has working data connection with the same phone settings.

Edit 2: When Googling, I found this log that also seems to be coming from a Droid 4, but probably still running GB: https://forums.motorola.com/files/bdcfc5cfaa/asi_logs-20120313-173332.log

D/SetupPhoneService(724)onCreate
D/SetupPhoneService(724)phoneStatus = 0
V/VVMReceiver(1615)onReceive
D/VVMReceiver(1615)Subscription state : 3
D/VVMReceiver(1615)SIM_STATE_CHANGED intent received::myString: LOADED
D/SetupPhoneService(724)SIM Card state READY
D/SetupPhoneService(724)SIM operator = 311480
V/VvmService(1615)Creating VvmService
D/SetupPhoneService(724)SIM type APPTYPE_USIM
[COLOR="Red"]V/VvmService(1615)NetworkType = 2, Phone_FEATURE_ENABLE = enableMMS
D/SetupPhoneService(724)SIM type APPTYPE_CSIM
D/SetupPhoneService(724)SIM type APPTYPE_ISIM
D/SetupPhoneService(724)MDN = 7066147687
D/SetupPhoneService(724)SIM is a valid activated Verizon 4G SIM

[/COLOR]

So it's saying the Vodafone SIM is not 4G, which is true, but neither is the Telfort SIM (as far as I know - 4G is still faaar away here).