My life has just been changed. It turns out you can sideload the #Zotero Android app onto a #Supernote, and then actually get access to all your Zotero synced files. It's a teeny bit involved, but mangeable:
1. Go to Supernote settings>Security & Privacy and enable side loading. This will turn on the USB port for Android debug tools.
2. Install the #Android platform tools (on Mac `brew install android-platform-tools`)
3. Grab a nightly build from https://github.com/northword/zotero-android-nightly-build of it.
4. Connect Supernote to a computer (in my case a Mac).
5. Run `adb install $filename.apk`
It will now be in your "sidebar". It might be under "more". But I was able to log in, and it synced 2,000ish documents in just a couple minutes. Obviously you need to be on WiFi for this.
6. If you're paranoid, turn off side-loading.
The reader has full markup capabilities, and syncs quite quickly back. See attached screenshots.