@mshibo
What is the difference between that " one-package firmware " that you flashed and standard firmware dependent on the device model ? Is it some modified firmware or what ?
Well, sboot method is kinda old now and it has been patched in a lot of devices and even for most of old devices too as they've got new updates with new security too. I used it before and it was working well but now I believe it's useless.
There 2 different issues here. Flashing older sboot would allow to use some bootloader exploit but not much beside it. It's also limited by the "binary" version since S6 which is why it's not possible to downgrade it too much but also lowers a chance to brick the device.
Flashing patched boot would allow disabling or remove usercode, enable adb and do any other nice stuff but there is FRP and engineering boot images usually only have ADB enabled (still requires authorization) and are sometimes rooted, but do not remove usercode from my experience.
This is actually weird that flashing this firmware that contain boot, recovery and system image removes the code. I checked it with the same stock firmware version, unpacked all 3 images and both boot.img and recovery.img are same as in stock firmware so it's not even an engineering rom. system.img differs (so FRP should block writing it, right?) but once unpacked there seems to be couple changes in build.prop only and those are insignificant. They changed codename, all_codenames, security_patch, and model strings to their team name (same as website address). Nothing else was changed from what i see. If it works, then it seems to be some kind of bug rather than a solution that can be used on different models or variants.
There is a box/tool (BMT PRO) that is supposedly able to patch firmware to remove usercode on couple new Samsung phones (A3 2016, J7 2016 and 2017, S7 etc) despite FRP on, OEM unlocking off and without tripping Knox. No idea if or how well it works.
I ask myself on what assumptions I would eTrust. This post is an obstacle I know, but nobody wants to face the problem of eTrust.
Its not only my problem. Its alls problem. But pushed-aside. I want to solve it.