Trying to flash regular openwrt images to emmc partitions, but was only able to find instructions for bpi R3, not R4 lite. I tried it for R4 lite with files for openwrt standard v25 rc4, but could not boot from emmc partition after that. Here are the instructions I followed, apart from partitioning, since that had already been done by banana-pi emmc installation image.
#dd if=immortalwrt-mediatek-filogic-bananapi_bpi-r3-mini-emmc-gpt.bin of=/dev/mmcblk0
echo 0 > /sys/block/mmcblk0boot0/force_ro
#dd if=/dev/zero of=/dev/mmcblk0boot0 bs=512 count=8192 conv=fsync
#dd if=/dev/zero of=/dev/mmcblk0 bs=512 seek=13312 count=8192 conv=fsync
dd if=immortalwrt-mediatek-filogic-bananapi_bpi-r3-mini-emmc-preloader.bin of=/dev/mmcblk0boot0
dd if=immortalwrt-mediatek-filogic-bananapi_bpi-r3-mini-emmc-bl31-uboot.fip of=/dev/mmcblk0p3
dd if=immortalwrt-mediatek-filogic-bananapi_bpi-r3-mini-initramfs-recovery.itb of=/dev/mmcblk0p4
dd if=immortalwrt-mediatek-filogic-bananapi_bpi-r3-mini-squashfs-sysupgrade.itb of=/dev/mmcblk0p5