On first startup VIM1 runs Android directly from its EMMC. Even if you correctly burn an Linux Ubuntu/Debian image, the one that Khadas provide, VIM1 with Android doesn’t boot the USB but directly boot from EMMC
I was able to wipe the EMMC and install Ubuntu on it as explained here
After that I was able to connect via SSH using khadas@192.168.1.26
With Ubuntu running the white LED flash in an heartbeat fast mode (with Android it has an heartbeat slow mode)