Been a while since I worked on this. My ultimate conclusion at the time was that the device was a very well made bit of hardware that could have been incredibly useful in a lot of fields, but lack of developer documentation limited it to only being used for garmin products. Frustratingly, although the Ant protocol is supposed to be open, garmin shipped this device using an ANT encryption key that will not allow the extended device profile to be activated without it, as in, it won't connect to anything that isn't garmin, and developers cannot use the profile. Developers were only ever given access to simulate their own garmin compatible sensors, etc. So without a garmin controller, the display refuses most modes including the extended display profile.
Really wish they would release a new version and give us real access to put anything on the screen using any BLE device like a ESP32...
After all this time, I can't remember the reason, but I was fairly certain that the EXD profile did allow for an image to be uploaded. I observed something that convinced me. The problem was not having the key / documentation on protocol to do it.
Anyone else made progress on this? I've since sold my device, but I might buy another if anyone is still working on this.
[ Edited: 05 August 2023 04:31 AM by Redacted ]