Repurposing an Old Tablet: A Time Hole of SDKs, Bootloops, and Stubborn Curiosity

What started as a small idea — turning an old Samsung Galaxy Tab 4 (SM-T230NU) into a dedicated FluidNC pendant — turned into a full dive into Android development, debugging, firmware archaeology, and system recovery.

Here’s the real takeaway from today.

Coming Up With a Simple Goal

The original goal wasn’t complicated:

• Old tablet
• FluidNC web interface
• Fullscreen
• Landscape
• Launch on boot

A normal person would’ve added the webpage to the home screen in Chrome and been done with it - and I might regret not stopping there - but it all came from curiosty.

Learning the SDK Environment

I spent time in Android Studio learning:

• How project structure is laid out
• Where manifests, layouts, Kotlin files, and themes actually live
• How Gradle build files fit together
• How SDK versions impact compatibility

I went from not knowing where things were to being able to navigate the project tree quickly and edit the right files without guessing.

I built a working APK — even if the target browser engine didn’t support what FluidNC needed, the app did exactly what I wrote it to do.

Using ADB and PowerShell

I pushed deeper into device-level interaction:

• Installed platform-tools
• Added ADB to system PATH
• Queried the device
• Verified connection in developer mode
• Used ADB to sideload, inspect, and test

Following the Rabbit Hole Further

Once it became obvious that Android 4.4 was the real limitation, not the app, I kept going.

That led me into:

• Hunting down discontinued libraries (Crosswalk, old .aar packages)
• Trying different browser runtimes
• Experimenting with launching Chrome in kiosk-like modes
• Testing fullscreen flags and orientation locks
• Dealing with missing APIs and deprecated functions

It stopped being about FluidNC at that point.
It became about a carefree environment for testing Android development that sparked from a simple project.

Stepping Into Firmware Territory

When software limits hit a wall, I decided to try upgrading the tablet entirely — aiming for LineageOS or anything newer than KitKat.

That started a different rabbit hole:

• Searching for factory firmware for a device long out of support
• Sorting through mismatched builds and dead download links
• Learning how PIT files map partitions
• Understanding (or trying to) why Odin fails during writes
• Flashing TWRP
• Watching the tablet "soft-brick" into recovery loops
• Figuring out how Samsung’s download mode actually behaves
• Attempting to restore system partitions manually

A lot of it was trial and error.
A lot of it was frustrating.
None of it was wasted.

It was about chasing a small idea until it forced me to learn:

• Android app fundamentals
• Legacy WebView limitations
• How Chrome vs system web engines differ
• ADB usage
• Firmware flashing and partition mapping
• Bootloader interactions
• How older hardware complicates everything

And honestly — it was interesting the whole way through.

Even if the tablet fought back at every step, I walked away knowing a lot more than when I started.