Take a fresh Ubuntu 16.04 or centos,debian,run this command
wget http://download2.mikrotik.com/routeros/6.36.4/chr-6.36.4.img.zip -O chr.img.zip &&
gunzip -c chr.img.zip > chr.img &&
mount -o loop,offset=33554944 chr.img /mnt &&
ADDRESS=ip addr show eth0 | grep global | cut -d' ' -f 6 | head -n 1 &&
GATEWAY=ip route list | grep default | cut -d' ' -f 3 &&
echo "/ip address add address=$ADDRESS interface=[/interface ethernet find where name=ether1]
/ip route add gateway=$GATEWAY
" > /mnt/rw/autorun.scr &&
umount /mnt &&
echo u > /proc/sysrq-trigger &&
dd if=chr.img bs=1024 of=/dev/vda &&
reboot
For default root password = "xxxxxx"
wget http://download2.mikrotik.com/routeros/6.36.4/chr-6.36.4.img.zip -O chr.img.zip &&
gunzip -c chr.img.zip > chr.img &&
mount -o loop,offset=33554944 chr.img /mnt &&
ADDRESS=ip addr show eth0 | grep global | cut -d' ' -f 6 | head -n 1 &&
GATEWAY=ip route list | grep default | cut -d' ' -f 3 &&
echo "/ip address add address=$ADDRESS interface=[/interface ethernet find where name=ether1]
/ip route add gateway=$GATEWAY
/ip service disable telnet
/user set 0 name=root password=xxxxxx
" > /mnt/rw/autorun.scr &&
umount /mnt &&
echo u > /proc/sysrq-trigger &&
dd if=chr.img bs=1024 of=/dev/vda &&
echo "sync disk" &&
echo s > /proc/sysrq-trigger &&
echo "Sleep 5 seconds" &&
sleep 5 &&
echo "Ok, reboot" &&
echo b > /proc/sysrq-trigger