I.mx6 quad with debian image stops on reboot command and not restart

Reboot command operates successfull while stopping devices and processes.
But at the end, the system stopped and rebooting is not triggered.
This is the output:
[ 518.428843] ci_hdrc ci_hdrc.1: remove, state 4
[ 518.433339] usb usb2: USB disconnect, device number 1
[ 518.438417] usb 2-1: USB disconnect, device number 2
[ 518.445354] ci_hdrc ci_hdrc.1: USB bus 2 deregistered
[ 518.450617] imx2-wdt 20bc000.watchdog: Device shutdown: Expect reboot!
[ 518.457313] reboot: Restarting system

The system remains at last line forever. Does not reboot.
Previous line notifies watchdog: Device shutdown: Expect reboot!

Any suggestions what is happen ?

It is most likely the device is rebooting and then not able to initialize the sdhc card to reload the bootloader. You can verify this happening by plugging in a usb-a to usb-a cable into a computer and see if the device is in SDP recovery mode. I generally use a usb-a to usb-c cable and then a usb-c female to usb-a male adapter as the USB-C spec requires a resistor on the VCC line and this will protect both devices from power surges.