ERos 4G-IOT communicator phone

Some known broblems for Orange pi 4G-IOT board.

There is not known method (without flashing) to boot from sd card installed Ubuntu image which manufacturer give!!

With stock android 6 I installed 1.7Ah battery and it loaded to 100% but when I remove powercable phone crash.

Device don't have fastboot, atleast adb reboot fastboot dosn't work.
Anyway adb reboot recovery works but there are no volume buttons to select menuitem: updates from sdcard.

Orange PI 4G-IOT official build script fails in 32-bit enviroment (Ubuntu 18.04):
/bin/bash: /home/eros/src/OrangePi4G-iot/uboot/preloader/tools/dct/DrvGen: cannot execute binary file: Exec format error

eros@sonata:~/src/OrangePi4G-iot$ file /home/eros/src/OrangePi4G-iot/uboot/preloader/tools/dct/DrvGen
/home/eros/src/OrangePi4G-iot/uboot/preloader/tools/dct/DrvGen: ELF 64-bit LSB executable, x86-64, version 1 (GNU/Linux), dynamically linked, interpreter /lib, for GNU/Linux 2.6.24, BuildID[sha1]=3948dde96841aca27a8cc3df9e336f41a4164761, not stripped

There is only 32-bit kernel (arm7l v4) pre compiled (android 6). It is not clear yet is it posible to compile official kernel sources produce 64bit kernel.
NixOS support needs 64bit kernel. CPU is 64bit Cortex A53.

eros@sonata:~/src/OrangePi4G-iot/kernel$ make ARCH=arm64 defconfig 4g-iot_linux_defconfig
*** Default configuration is based on 'defconfig'
warning: (ARM64) selects DT_IDLE_STATES which has unmet direct dependencies (CPU_IDLE)
warning: (ARM64) selects DT_IDLE_STATES which has unmet direct dependencies (CPU_IDLE)
# configuration written to .config
*** Can't find default configuration "arch/arm64/configs/4g-iot_linux_defconfig"!
scripts/kconfig/Makefile:105: recipe for target '4g-iot_linux_defconfig' failed
make[1]: *** [4g-iot_linux_defconfig] Error 1
Makefile:541: recipe for target '4g-iot_linux_defconfig' failed
make: *** [4g-iot_linux_defconfig] Error 2