Thanks the the link.
I see they have made config files for watchdog daemon that tells the hardware watchdog that the system is alive. But that is not exactly disabling ore removing watchdog from the system.

From what I found out the software lifeguard is DSME (Device State Management Entity) and I believe that it can be removed from the system. But services use dsmetool for startup. A have not found out yet what exactly does it do. But startup scripts can be rewritten not to use it so that should not be a big problem.

Is the hardware watchdog disabled if I use the kernel without it's support? Is some process writing data to watchdog devise the only solution to keep the system alive? Can I change some settings in kernel to disable watchdog (maybe some boot option)? Do flags that flasher can set change some settings in hardware (watchdog firmware ore something) and not only software?
Right now I am using a kernel without watchdog support. So even if there are some boot flags they would not work as kernel does not know about watchdog. So flasher must have changed something else when it enabled R&D mode.