Ditrih Bolen

Thanks Juan, I was able to boot the kernel with some changes.
 
I used this extlinux.conf file. Changed the kernel to /Image and fdt to /dtb. I manually created a directory called extlinux in the boot directory. I then moved the extlinux.conf there. 
/extlinux/extlinux.conf
label ARMBIAN kernel /Image fdt /dtb/allwinner/sun55i-a527-radxa-a5e.dtb append earlycon=uart8250,mmio32,0x02500000 clk_ignore_unused console=ttyS0,115200 loglevel=8 root=/dev/mmcblk0p2 rw rootwait  
radxa-cubie-a5e.csc
I changed one line BOOTSCRIPT="extlinux.conf"
# Allwinner Cortex-A55 octa core 2/4GB RAM SoC USB3 USB-C 2x GbE BOARD_NAME="radxa cubie a5e" BOARDFAMILY="sun55iw3" BOARD_MAINTAINER="Nick A" BOOTCONFIG="radxa-a5e_defconfig" OVERLAY_PREFIX="sun55i-a527" BOOT_LOGO="desktop" KERNEL_TARGET="edge" FORCE_BOOTSCRIPT_UPDATE="yes" BOOT_FDT_FILE="dtb/allwinner/sun55i-a527-radxa-a5e.dtb" BOOTFS_TYPE="fat" BOOTSCRIPT="extlinux.conf" IMAGE_PARTITION_TABLE="msdos" BOOTSTART="1" BOOTSIZE="512" ROOTSTART="513" UBOOT_EXTLINUX=yes" UBOOT_EXTLINUX_ROOT=root=UUID=%%ROOT_PARTUUID%%" UBOOT_EXTLINUX_FDT="sun55i-a527-radxa-a5e.dtb"  
Most Armbian boards use the boot.cmd for their bootscript. I found the line I missed in build/config/sources/families/sun55iw3.conf. I cloned a clean build and changed one line in sun55iw3.conf.
 
declare -g BOOTSCRIPT='boot-sun50i-next.cmd:boot.cmd'
 
declare -g ATF_TARGET_MAP="PLAT=sun55i_a523 DEBUG=1 bl31;;build/sun55i_a523/debug/bl31.bin" declare -g ATFBRANCH="branch:a523" declare -g BOOTSCRIPT='boot-sun50i-next.cmd:boot.cmd' declare -g BOOTDELAY=1 declare -g BOOTSOURCE='https://github.com/apritzel/u-boot'  
_ _ _ __ __ _ _ _ /_\ _ _ _ __ | |__(_)__ _ _ _ ___ _ _ _ _ ___ / _|/ _(_)__(_)__ _| | / _ \| '_| ' \| '_ \ / _` | ' \___| || | ' \/ _ \ _| _| / _| / _` | | /_/ \_\_| |_|_|_|_.__/_\__,_|_||_| \_,_|_||_\___/_| |_| |_\__|_\__,_|_| v25.02 rolling for radxa cubie a5e running Armbian Linux 6.12.12-edge-sun55iw3 Packages: Debian stable (bookworm) Updates: Kernel upgrade enabled and 6 packages available for upgrade Support: DIY (custom image) IP addresses: (LAN) IPv4: IPv6: Performance: Load: 5% Up time: 4 min Memory usage: 4% of 3.83G Usage of /: 3% of 58G Commands: Configuration : armbian-config Upgrade : armbian-upgrade Monitoring : htop nick@radxa-cubie-a5e:~$  

Tonight, I finally managed to build an image on the OPI4a itself. However, after writing it to the eMMC using Balena Etcher, the board did not boot. If I understood Nick A's message correctly: 'Orangepi 4a uses the same radxa-a5e_defconfig. https://github.com/warpme/minimyth2/blob/master/script/bootloaders/board-t527.orangepi_4a/Makefile', I needed to select the radxa-a5e board from the list.
Here's what I did:
bash
git clone https://github.com/NickAlilovic/build.git --branch warpme-6.12 --single-branch cd build ./compile.sh
I selected the radxa-a5e board, edge, bookworm, server, standard. The image was compiled, and then I wrote it to the eMMC via Balena Etcher.
After powering on, the board shows no signs of activity. I suspect that some patch or bootloader was not included in the image. Unfortunately, my knowledge is insufficient to understand what I did wrong and how to fix the issue. I kindly ask for your help.