RB750/g becomes inaccessible after loading openwrt

RouterOS General
1

There is RB/750g with RouterOS 4.10
Immediately after creating OpenWRT environment ( http://wiki.mikrotik.com/wiki/Metarouter )
routerboard had rebooted by watchdog, then become inaccessible:
nmap displays open ports for www, ssh, telnet, winbox, but no answer on all of them.

After resetting via reset hole ( http://wiki.mikrotik.com/wiki/Manual:Password_reset )
routerboard answers to ping, but all connections are died by timeout:

# telnet 192.168.88.1                     
Trying 192.168.88.1...                                                    
Connected to 192.168.88.1.                                                
Escape character is '^]'.                                                 

MikroTik v4.10
could not receive confirmation to CTRL_READY from loader
--- nv::message --------                                
------------------------                                
Connection closed by foreign host.

“MikroTik v4.10” is displayed after 30 secs delay, “could not receive …” after few minutes, “connection closed” after pressing Enter.

MAC of RB is not discovered by WinBOX nor NetworkInstall.
Outgoing network activity from RB:

# tcpdump -ntpi eth0    
tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on eth0, link-type EN10MB (Ethernet), capture size 96 bytes     
CDPv1, ttl: 120s, Device-ID 'MikroTik', length 61                         
IP 192.168.88.1.5678 > 255.255.255.255.5678: UDP, length 77               
CDPv1, ttl: 120s, Device-ID 'MikroTik', length 61                         
IP 192.168.88.1.5678 > 255.255.255.255.5678: UDP, length 77               
IP 192.168.88.1.5678 > 255.255.255.255.5678: UDP, length 77               
CDPv1, ttl: 120s, Device-ID 'MikroTik', length 61

Only after hard resetting ("Hold reset button during boot time longer, until LED turns off)
RB was resurrected with default settings and without openwrt.

Is it a bug or a feature???

2

The RB750/750G has only 32MB of RAM, so you’re already pushing your luck when it comes to MetaRouter which requires 16MB RAM unless you run OpenWRT you might get away with less than 16MB. I think the RB750’s CPU usage went up to 100% which looked like it denied access to everything.

I’m not an expert here, so you should consider other people’s opinions and answers too :slight_smile: