Hi, lava team!
First question:
I'm working with fastboot device, is it possible after test part put device again to fastboot mode, run some fastboot command ( not to flash ), boot
 again, run test. 
job steps:
- deploy lxc
 - boot lxc
 - test lxc
 - deploy fastboot ( put to fastboot )
 - boot fastboot device
 - run test
 - reboot and put device to fastboot mode
 - run fastboot commands
 - continue run test.
 
Can you give any advice how to do it?
Better to able reboot device inside test. I tried to reboot device from test part, lava just stuck and wait when reboot action will end. But looks like it does not recognize end. 
Second question:
In job have lxc namespace and device namespace, how to run command_action from host os, not lxc? 
Best regards,
Ilya Feduisv