Ubuntu Touch 24.04-2.x S-Pen test builds
Samsung Galaxy Tab S9 (gts9wifi, SM-X710) / Tab S9 Ultra (gts9uwifi, SM-X910)

Adds S-Pen (Wacom EMR) input, handled as a touchscreen: tap, drag, scroll.
Known limits of this mode: no hover cursor, no pressure/tilt in apps, side
button and eraser inert, no palm rejection. Pen and finger are two
independent touch inputs.

Flashing (TWRP)
---------------
1. Mount /data, then: adb push <zip> /data/
2. Install the zip from /data via the TWRP menu
3. Reboot with: adb shell twrp reboot system
   (a plain reboot from recovery lands back in TWRP)

Test checklist
--------------
- Pen taps land exactly under the tip; drag and scroll track the pen.
  Offset or mirrored taps = calibration matrix issue, report the direction.
- Finger touch unaffected, including with the pen in proximity.

gts9uwifi note: stock dynamic partitions imported from X910XXS6EZG3
(Android 16 firmware); CYG1 is no longer served by Samsung. Report anything
that smells like a vendor HAL mismatch.