I am able to build image for Raspberry Pi 3 Model B. I can flash the image on SD card (using dd command) and system comes up correctly. However when I build a new image after making code changes and try to upgrade to it, system no longer comes up. If I take the same image and flash it directly on SD card, all is fine. I can't explain why sysupgrade or upgrade via Luci fails. I don't know the exact nature of failure yet (I don't have RP3 connected to monitor) but I can't ping the system.
root@LEDE:~# sysupgrade -v /tmp/lede-brcm2708-bcm2710-rpi-3-ext4-sdcard.img Image metadata not found Saving config files... etc/config/dhcp etc/config/dropbear etc/config/firewall etc/config/luci etc/config/network etc/config/rpcd etc/config/system etc/config/ucitrack etc/config/uhttpd etc/config/wireless etc/dropbear/dropbear_rsa_host_key etc/group etc/hosts etc/inittab etc/luci-uploads/.placeholder etc/opkg/keys/5151f69420c3f508 etc/opkg/keys/5e773ca0481d1c2 etc/opkg/keys/72a57f2191b211e0 etc/opkg/keys/792d9d9b39f180dc etc/opkg/keys/9ef4694208102c43 etc/opkg/keys/b5043e70f9a75cde etc/opkg/keys/dace9d4df16896bf etc/opkg/keys/dd6de0d06bbd3d85 etc/passwd etc/profile etc/rc.local etc/shadow etc/shells etc/sysctl.conf etc/sysctl.d/local.conf Sending TERM to remaining processes ... ubusd askfirst askfirst logd rpcd netifd odhcpd uhttpd ntpd dnsmasq Sending KILL to remaining processes ... askfirst askfirst Switching to ramdisk... Performing system upgrade... 21+1663 records in 21+1663 records out Upgrade completed Rebooting system... umount: can't unmount /dev/pts: Resource busy umount: can't unmount /dev: Resource busy umount: can't unmount /tmp: Resource busy