You have much better options.
Most ThinkPad X series tablets and certain S series yoga models support
free/libre firmware (coreboot).
Available models include X41t, X60t, X61t, X200t, X201t, X220t, X230t, X1
Helix (1st gen. with IvyBridge CPU) and S1 Yoga (1st gen. with Haswell CPU).
All these models don't have Boot Guard. Their Wacom digitizer pen solutions
are perfectly supported by free/libre GNU/Linux distributions.
I tested Krita on (most of) those devices using Debian testing (KDE edition)
without any non-free firmware. I can take notes or draw pictures freely.
