We're not completely sure how to do things, but here's what we want:
To keep our dev cycle fast, we'd like to have a fast way to send our custom kernel (which is currently about 2MB) to the device and boot it. Right now we use Uboot to send it via y-modem, but that costs us minutes (at 115200 baud). Other options we have thought about, is using the sd-card slot to boot from, and use a microsd switch to copy stuff on there. But it seems that uboot is unable to access the sd card.
Have you any suggestions for us?
There is a guide that explains how to boot the Edison from the SD card How to boot Edison from an SD card (Linux) however I haven’t tried it with a custom kernel. Give it a try and let me know if this works for you.
There is also an official Github on U-boot that might be helpful as well 01org/edison-u-boot · GitHub