MOBILE DATA Not Working in Custom Roms in Roaming...!
Dear Users & Developers,
I'd like with the fewer words possible to address to you a strange behaviour of my custom ROM Redmi 4x...
1. The last 12 months I got it, Mobile Data never worked while in Roaming (Europe to Europe). Though not a big issue, I tried every thinkable method I know (just as a simple power user...) with no results on my custom "miuipro" ROM (miui 9, android v7.1.2 Beta). Only some custom ROMs like LineageOS and dotOS did offer me Mobile Data while in Roaming...
2. First of all, NOT any SIM problem.
In another phone, mobile data is up & running... (but no VoLTE cos my carrier does not support it)
3.
The strange thing: The "network test" (part of the "Security" suite of miui 9) reports always "your mobile data cannot be used
in roaming". However, I did manage (by experimenting with granting more permissions in AFWall+ application) to get K-9 Mail functioning quite well except when it comes a 8080 connection for opening a link in Browser (the connection
never get established). I was wondering if I messed things up with my AFWall+ firewall and santoni΄s in-build firewall settings or if something happens with port 80 and browsing. Furthermore, I repeatedly used commands like "settings -c put global data_roaming 1" from terminal as root (not adb) without any success. Needless to say that while in Roaming, voice/sms and wifi are
perfectly working...
4. When I got the idea to study the recovery reports, I discovered in the build.prop file the entries ro.com.android.mobiledata & ro.com.android.dataroaming as "FALSE" but I don΄t think this as an issue, since with the same readings I get always Mobile Data (in my country).
5. The Last and confusing part: Recently I tried 2 other miui 10 custom ROMs (one Global and one miuipro) keeping a backup image of my current ROM (with RedWolf custom recovery). It was then I realised 2 strange things: (a) when I restored that backup image by RedWolf I totally lost Mobile Data (being in my country). I was thinking that something may happened with partitions and when I did a clean install of my favour "miuipro" ROM (miui 9, android v7.1.2 Beta) I did and does have Mobile Data again! (I restored my data from both miui backup and Titanium). (b) However, starting again to search for a solution by ADB/terminal wayouts I came up with link
https://android.stackexchange.com/questions/77008/modify-settings-parameters-through-database and an astonishing conclusion: I never realised that I DO NOT have/see any .db folders (and files inside) in my /data/data folders for system apps, especially in "com.android.providers.settings", where Roaming settings are stored... The particular folder contains only EMPTY "cache" and "code_cashe" subfolders. The same for "com.android.providers.telephony", "com.android.provider.proxyhandler" and so on.
This is my problem so far, simple to check it from scratch but I failed so many months to realise...
I΄m thinking to start reviewing my older image backups just to check if the .db folders/subfolders are included there...
Last piece of info, my original miui version of the phone (6.0.1/MMB29M/v8.5.4.0.MAMCNED did NOT get Mobile Data Roaming as well.
But basically, I΄m in your hands, if any colleauge, poweruser, developer reads and has something to say... and thank you in advance!