"Invalid Sim Card" only when overseas

[matticas]

Hello,

I had my M8 replaced under warrenty and received a brand new M8. I am in Australia and use the Telstra network, and they provide network unlocked phones for plan customers, thus this phone isn't network locked.

When I first got it, it kept saying "Invalid Sim Card" on the lock screen for 2 days, and it went away by itself. The tech at the store said at that time they had significant network problems and we're resolved at the same time my phone was playing up. In those 2 days I also replaced the Sim Card and it made no difference.


Flash forward 4 weeks and I went overseas to Germany and the phone worked fine for a few days then again said Invalid Sim Card. No matter how many times I rebooted it I couldn't get it onto the network. Once I returned to Australia it worked fine.

I am now in South Africa and my Australian Telstra Sim Card was working fine but I needed a local number for data, so I purchased a Vodacom sim with data only and it worked straight away. My girlfriend also brought a Vodacom sim for her M10 (same Telstra plan as me) and hers is fine

My sim and phone ran on their networks fine for 12 hours and I wake up this morning and it's now saying "Invalid Sim Card" again. I've tried rebooting it several times with no luck.

Does anyone have any ideas?

I'm not convinced it's the Sim Card tray as it works fine on Australia, only when overseas. I don't know anything about the radio or baseband stuff but it's that related?? What can I check??

I used the IMEI24 website to confirm the phone was unlocked from the carrier, and entering *#*#4636#*#* doesn't show any info as it's not on the network.

Phone is currently unlocked, S-on, TWRP 3.0.2.0, rooted, Marshmallow.

I'm pretty angry as I have an ultra marathon in 2 days, and this phone was to connect my Garmin watch to the internet so my friends and family could track me, and most importantly my girlfriend could find me at the finish.

Any help would be greatly appreciated.

Thanks!

 

[redpoint73]

I don't know anything about the radio or baseband stuff but it's that related??

I doubt it has anything to do with radio baseband. GSM bands are pretty standard worldwide, and just about any "quad band" (850, 900, 1800, 1900) GSM phone should get you at least voice and EDGE data services. And all M8 versions support those GSM bands. Therefore, any M8 should get you at least GSM service, regardless of the radio baseband installed.

I wonder if the issue is the SIM modules themselves, and the "overseas" issue is a red herring? My thought is, that maybe the overseas SIMs you purchased don't quite fit as well as your local (Australian) SIM. One thing you can try, is put some Scotch tape on the SIM (on the side without the gold contacts) and see if that "fattens" up the SIM enough to make better contact. Be careful not to get tape stuck in SIM slot/tray. I've seen this trick work for some folks with the Invalid SIM error.