Samsung Galaxy S7 Active AT&T Firmware Needs a Downgrade from Oreo to Nougat
Samsung Galaxy S7 Active AT&T Firmware Downgrade
I bought 2 of these Samsung Galaxy S7 Active AT&T branded phones off ebay USA and got 'em delivered to Australia. Both of these phones were working perfecty alright with the old firmware installed (I'm reasonably sure the firmware was Android 7 Nougat), until I forced the new firmware update by manually updating the firmware to Android 8 via Odin.
We have got 3 major telcos and numerous MVNO's(Mobile Virtual Network Operators) in Australia and both of these above-mentioned phones were working with all 3 major telcos and all of their MVNO's before I forced the firmware upgrade via Odin. Now, out of these 3 network operators Vodafone and its MVNO's sim cards has stopped working. Both phones working perfectly fine with other 2 network sim cards. I believe this has got something to do with the operating system upgrade as both of these phones having difficulty making/receiving calls on Vodafone network (I'm able to send/receive messages sometimes with long delays, though ). The new firmware must have disabled few of the frequencies/Network bands. The following link might help that has got the operating frequencies of these 3 networks
I am attaching the current software information and I want to downgrade the operating system(Firmware ) back to Android Nougat. I'm not worried about Rooting/Warranty/Official Status etc. I just want these phones to keep working for all 3 networks.
A supplementry question is that most of the time these phones do not show callers' number, even though the caller has got 'Show my number' enabled and that number is shown on all other phones but except these 2. All the right settings enable on the caller's phone. I am using Optus network sim cards in these handsets at the moment.
I have tried to downgrade the firmware by myself but could not get the right/easy to follow step-by-step information on the different tech forums. I think for the experts, it won't be a very hard task. Any help will be appreciated. Thanks