What this browser is and what it exposes. The memory numbers feed the 2 GB versus 4 GB board decision.
The demo does not run in a browser tab, it runs as an installed portrait fullscreen app under screen pinning. Everything below must be re-tested from the installed app, not from the tab that installed it.
Claiming an interface is not the same as moving data. These buttons enumerate, claim, then run real control transfers and time them. Test article: any vendor-class device. An ST-Link (VID 0x0483) works, and the Nucleo has one on its debug port.
Pick the portrait trade-fair video. It plays muted and looped exactly as the screensaver will. Dropped frames here, especially while the soak test is hammering USB, is what disqualifies a board.
A fair day is eight hours. Start this with the video playing and a device claimed, then leave the tablet alone on the bench. Disconnects, rising memory or a creeping transfer time are the failures that only show up after hours.
There is no usable wifi in a booth. The service worker caches the whole app shell. To verify: load once online, then turn on flight mode and relaunch from the home screen icon.