Ok, so I got myself an MTS MTAG 3.1 (Huawei C8511)/(Huawei C8500S China Telecom) which was ruim unclocked but data incompatible for Reliance. This guide works for other various Android non-OMH CDMA handsets as well. This is for those whose APN list is not editable or custom APN cannot be saved.Tested. This is my sole invention and work and is not published anywhere else till now. Use is as per your discretion.
1. Make sure the handset is rooted and busybox and SU are installed and updated.
2. Open Root explorer and allow SU permission if opened for the first time.
3. Delete the cust folder in the root system of the device. This folder carries operator files, multimedia, operator apks and NV traces.
4. goto apns-conf.xml in /system/etc folder
5. Longpress on apns-conf.xml and select open in text editor
6. Once the text editor pops up, scroll down and you will see China Telecom, Sprint, Verizon, M-pcs, Virgin, APNs list.
7. Edit the first APN (default one) with Reliance APN settings we all know here.
8. Keep changing all the APNS till down with various settings. Once can edit the defualt value with usr=net/pass=net and the other ones with mdn/mdn combination.
9. Be careful do not put any extra space or delete any comma or double colon.
10. Click to save and exit, original bak will be backed up automatically.
11. Goto root using root explorer and in system folder locate build.prop
12. Longpress and open using editor
13. Goto ro.cdma.home.operator.numeric= ____ change it to 404 00 and ro.cdma.home.operator.alpha=______ change it to Reliance
14. This can be a little troublesome so bak is imp. Click to save and exit.
15. Reboot.
16. In some devices, the APN list in Network settings gets automatically updated, in some you have to put it manually but now the custom APNs will be saved.