Wiki:
https://variwiki.com/index.php?title=DART-6UL_Yocto&release=mx6ul-yocto-kirkstone-5.15.71_2.2.0-v1.3
Release notes:
https://variwiki.com/index.php?title=DART-6UL_Release_Notes&release=mx6ul-yocto-kirkstone-5.15.71_2.2.0-v1.3
Create demo SD card:
https://variwiki.com/index.php?title=Yocto_Recovery_SD_card&release=mx6ul-yocto-kirkstone-5.15.71_2.2.0-v1.3
SOMs specifications:
https://www.variscite.com/product/system-on-module-som/cortex-a7/dart-6ul-freescale-imx-6ul/
https://www.variscite.com/product/system-on-module-som/cortex-a7/var-som-6ul-nxp-imx6ul-6ull-6ulz/