I've always been a tech guy and wanted to know how internet works in real life. Have been seeing Reddit posts in subreddits like r/homelab and r/selfhosted on building a Homelab or self hosting something or the other for a long time and always wanted to do it myself.
So I picked up an old Samsung Galaxy Grand Neo Plus (GT-I9060I), running Android 4.4.4 KitKat, 1GB of RAM which has been lying around for a very long time and tried to make it my time Homelab server.
The phone was already 12 years old and the screen was 50-60% broken so I tried to use Scrcpy to access the screen through laptop but then when I read the Scrcpy docs, I realised that it supports Android 5 and above. So I tried Vysor which has a support for phones with Android 5 and below and its free tier was good enough for my use case. Later I realised that the chipset was Spreadtrum SC8830 which is a brand notorious for not open-sourcing anything, which matters a lot later.
Funny how I had to press the build number 7 times to access Developer Options which is an intentionally goofy Easter egg that Google still ships today. Then finally abd devices showed a serial number instead of showing an empty string and finally Vysor started gave me the access to the phone screen.
Where it all started to go wrong
The real goal was root access, so I could run Linux Deploy and get a proper Debian chroot environment on the phone. I tried every tool one by one to get the root access but all of them failed because they all depend on servers that no longer exist. TWRP wouldn't fit cleanly into the recovery partition via button beacause along with screen even the buttons were not functioning and TWRP got cleared when the phone was rebooted. So I got an idea.
I manually unpacked the stock boot image with magiskboot, patched the ramdisk by hand to disable Android's secure boot properties, repacked it and flashed the result into the recovery partition as a workaround, intending to boot a 'trojan horse' Android instance with root already enabled, then use that to disable the security script that kept deleting TWRP.
This is not a well known safe procedure. It's an improvisation, and it's the point where things actually broke. The bootloader found a modified kernel sitting somewhere it didn't expect and started panicking. The phone got stuck on the Samsung splash screen and started overheating (which is a typical kernel panick situation). I tried to turn the phone off by removing it's battery, plugging it again and switching it ON again and again, yet it did not work.
There was only one last resort and it was to reflash the stock images. As soon as I did that a red exclamation mark appeared in Download Mode alongside 'Secure Boot: ON'
Samsung's Knox security fuse, tripped and this fuse is a one-way switch. Once it's tripped, no amount of reflashing stock firmware undoes it. The device was dead 🕊️. Well I didn't have any remorse for it. It was anyway an almost dead phone but it was worth it. Atleast I learned something new.
I have another old Samsung J7 lying around getting dusted, so i'll be using it for my next experiment and i'll probably use Termux this time beacause I think this phone can run Termux on it. Hopefully.