You need to modify the the u-boot environment in order to boot a mainline kernel.
- The console device is now
ttyAML0instead ofttyS0 - The dtb is called
meson-gxl-s905x-khadas-vim.dtbinstead ofkvim.dtb - The kernel Image is called
uImagean has to be started withbootm 0x1000000 0x2000000 0xc00000
I’m using the latest u-boot now, but the mainline kernel should boot with the previous version as well.
You may take a look here, I’ve started to write my own set of u-boot macros which makes it easier to manage different configurations at a time and choose a distinct one for booting.