Xperia Z Ultra can use the pen or pencil made of wood or metal as stylus, but Z1's screen also supports it and Sony disabled it for some reason.
root is needed to enable this.
To enable pen mode, there's three methods.
One of them is enough.
● Create init.d script in /system/etc/init.d (requires init.d support):
#!/system/bin/sh chown system:system /sys/devices/virtual/input/clearpad/pen echo 1 > /sys/devices/virtual/input/clearpad/pen
chown system:system /sys/devices/virtual/input/clearpad/pen echo 1 > /sys/devices/virtual/input/clearpad/pen
I created pen mode enable/disable toggle app with Tasker.
Now you can use anything made of wood, metal or rubber.
I couldn't use a plastic pen, though...
I recommend changing one value in /system/usr/idc/clearpad_pen.idc for more accuracy.
# Pressure touch.pressure.scale = 0.2
# Pressure touch.pressure.scale = 0.1
there is "grove" but I could only show circle with pen and I couldn't use with glove.
Thanks championswimmer for finding this.