More about DOS drivers with Booklet 3G.
Hard Disk Interface: It is actually PATA(IDE) compatible with uSATA adapter so it is very DOS compatible, but remember some DOS versions has max HDD/SSD size limits. I think the only fdisk partitioning tool for DOS that support over 137GB drives come with FreeDOS 1.3 and newer. And FreeDOS can access partitions after 137GB.

Screen: All VESA 3.0 compatible screen modes should work up to 1280x720.

Touchpad: All mouse drivers that support PS/2 works fine (driver comes with FreeDOS).

USB: You can boot from with USB-floppydrive and USB-CDROM without drivers. But also Panasonic USB-drivers work in DOS.

HDMI: If cable connected, Booklet only shows to HDMI, not screen. All VESA 3.0 modes up to 1920x1080 should work,. Automatic low resolution upscale (example text resolution 40x25 to 640x480 video)!

Speakers/Heasphone-output: Sound Blaster emulation should work, but it need JEMM, JEMMEX or QEMM memory manager and default settings of those memory managers are not good for Booklet. Is there any DOS gurus, who can help with DOS memory managers?