Francisco_xf

I just found the problem! I just commented the parameter CONFIG_DRAM_CLK from u-boot defconfig (sunxi_Gemei_G9_defconfig) and the problem is gone. Thank you very much for yours tips Gunjan!

Interesting...I tested the 32-bit Allwinner kernel before we release on a H3 board and it was booting.
 
You can give images from the archive a try. You can also try creating image yourself, Use branch as edge and it will create an image with 6.6 kernel. Instructions for building an image can be found here - https://docs.armbian.com/Developer-Guide_Build-Preparation/

if you can mount the sdcard and see the contents, then try editing boot/armbianEnv.txt file and the following at the end of. the file
 
earlycon=on extraargs=debug verbosity=7 console=serial  
This will get you more output on your serial port and then we can proceed based on the same

Probably, it will also be a good idea to add
fdtfile=sun4i-a10-gemei-g9.dtb Just to make sure that your device specific device tree is used.