I live in Eastern Europe, which is on the far side of the Samsung support network and I have samsung galaxy s3 phone (GT-9300 i guess). My repair options look a little bit bleak. I must either ship it back to France, from where it is bought, or I must seek help of non-licensed technicians. Thank God, there are quite a lot around here and for problems like this they do wonders.
I am worried though that the technicians may try to meddle with the software of my phone and do something nasty with it while the phone is in their possession. I use the phone quite a lot to access various servers trough ssh and the servers contain semi-sensitive information about customers, phones, the equivalents of social security numbers in my country and etc. Of course I will delete my present information, but how about the future. If someone has hacked versions of the firmware, it will be a child game to get the passwords for my servers.
So I need to secure the software of my phone somehow and I'm not sure of my options, so I'm asking for advice which is better. I have experience with Linux, but about Android I'm a quite noob. I had my Amazon FireHD Tablet rooted and installed with CyanogenMOD, so I know a little bit about ROM images. The phone itself is unrooted with original software and is not locked to a carrier.
1. Try to back up my entire ROM image?
There are various questions here. It looks that I cannot download standalone original ROM image directly from Samsung so I must back up mine. But in the bootloader (which opens with volume up/down + home + power) it seems that there are no options for backing up rom image, only for restoring trough ADB of SD card. Should I try to root, install alternative bootloader and then back up everything.
There is one very important sub-question here: Will the phone signal me somehow If someone replaces the original bootloader with say, non-signed one? What If someone changes the bootloader as well as the system image?
2. Should I try to ecrypt my phone.
I cannot get easily information about what exactly is encrypted. Pretty sure that the bootloader itself cannot be encrypted anyway. How about the system image. Is it encrypted ?
I'll be thanful for any help about these two ideas as well as any others?