Caletronics

I too wanted to boot to a second partition and struggled. The workaround by @richardk sort of fixes of the problem but isn't a general solution. After examining the U-Boot environment (printenv at the u-boot prompt) and /boot/boot.cmd I feel that boot.cmd needs to be patched. If you set the boot flag on the second partition (parted or fdisk, etc.) then U-Boot correctly sets 'distro_bootpart' and thereafter uses '${devnum}:${distro_bootpart}'. I modified boot.cmd to follow the same convention, rebuilt boot.scr and it works.
 
*** a/boot.cmd 2020-03-29 11:47:02.268576905 -0700 --- b/boot.cmd 2020-03-29 11:55:28.541325423 -0700 *************** *** 18,25 **** echo "Boot script loaded from ${devtype}" ! if test -e ${devtype} ${devnum} ${prefix}armbianEnv.txt; then ! load ${devtype} ${devnum} ${load_addr} ${prefix}armbianEnv.txt env import -t ${load_addr} ${filesize} fi --- 18,25 ---- echo "Boot script loaded from ${devtype}" ! if test -e ${devtype} ${devnum}:${distro_bootpart} ${prefix}armbianEnv.txt; then ! load ${devtype} ${devnum}:${distro_bootpart} ${load_addr} ${prefix}armbianEnv.txt env import -t ${load_addr} ${filesize} fi *************** *** 34,71 **** if test "${docker_optimizations}" = "on"; then setenv bootargs "${bootargs} cgroup_enable=memory swapaccount=1"; fi ! load ${devtype} ${devnum} ${fdt_addr_r} ${prefix}dtb/${fdtfile} fdt addr ${fdt_addr_r} fdt resize 65536 for overlay_file in ${overlays}; do ! if load ${devtype} ${devnum} ${load_addr} ${prefix}dtb/allwinner/overlay/${overlay_prefix}-${overlay_file}.dtbo; then echo "Applying kernel provided DT overlay ${overlay_prefix}-${overlay_file}.dtbo" fdt apply ${load_addr} || setenv overlay_error "true" fi done for overlay_file in ${user_overlays}; do ! if load ${devtype} ${devnum} ${load_addr} ${prefix}overlay-user/${overlay_file}.dtbo; then echo "Applying user provided DT overlay ${overlay_file}.dtbo" fdt apply ${load_addr} || setenv overlay_error "true" fi done if test "${overlay_error}" = "true"; then echo "Error applying DT overlays, restoring original DT" ! load ${devtype} ${devnum} ${fdt_addr_r} ${prefix}dtb/${fdtfile} else ! if load ${devtype} ${devnum} ${load_addr} ${prefix}dtb/allwinner/overlay/${overlay_prefix}-fixup.scr; then echo "Applying kernel provided DT fixup script (${overlay_prefix}-fixup.scr)" source ${load_addr} fi ! if test -e ${devtype} ${devnum} ${prefix}fixup.scr; then ! load ${devtype} ${devnum} ${load_addr} ${prefix}fixup.scr echo "Applying user provided fixup script (fixup.scr)" source ${load_addr} fi fi ! load ${devtype} ${devnum} ${ramdisk_addr_r} ${prefix}uInitrd ! load ${devtype} ${devnum} ${kernel_addr_r} ${prefix}Image booti ${kernel_addr_r} ${ramdisk_addr_r} ${fdt_addr_r} --- 34,71 ---- if test "${docker_optimizations}" = "on"; then setenv bootargs "${bootargs} cgroup_enable=memory swapaccount=1"; fi ! load ${devtype} ${devnum}:${distro_bootpart} ${fdt_addr_r} ${prefix}dtb/${fdtfile} fdt addr ${fdt_addr_r} fdt resize 65536 for overlay_file in ${overlays}; do ! if load ${devtype} ${devnum}:${distro_bootpart} ${load_addr} ${prefix}dtb/allwinner/overlay/${overlay_prefix}-${overlay_file}.dtbo; then echo "Applying kernel provided DT overlay ${overlay_prefix}-${overlay_file}.dtbo" fdt apply ${load_addr} || setenv overlay_error "true" fi done for overlay_file in ${user_overlays}; do ! if load ${devtype} ${devnum}:${distro_bootpart} ${load_addr} ${prefix}overlay-user/${overlay_file}.dtbo; then echo "Applying user provided DT overlay ${overlay_file}.dtbo" fdt apply ${load_addr} || setenv overlay_error "true" fi done if test "${overlay_error}" = "true"; then echo "Error applying DT overlays, restoring original DT" ! load ${devtype} ${devnum}:${distro_bootpart} ${fdt_addr_r} ${prefix}dtb/${fdtfile} else ! if load ${devtype} ${devnum}:${distro_bootpart} ${load_addr} ${prefix}dtb/allwinner/overlay/${overlay_prefix}-fixup.scr; then echo "Applying kernel provided DT fixup script (${overlay_prefix}-fixup.scr)" source ${load_addr} fi ! if test -e ${devtype} ${devnum}:${distro_bootpart} ${prefix}fixup.scr; then ! load ${devtype} ${devnum}:${distro_bootpart} ${load_addr} ${prefix}fixup.scr echo "Applying user provided fixup script (fixup.scr)" source ${load_addr} fi fi ! load ${devtype} ${devnum}:${distro_bootpart} ${ramdisk_addr_r} ${prefix}uInitrd ! load ${devtype} ${devnum}:${distro_bootpart} ${kernel_addr_r} ${prefix}Image booti ${kernel_addr_r} ${ramdisk_addr_r} ${fdt_addr_r}