Upgrade went well. After restart, no contact to router or any device on network. Entire network down. How to contact 750g to downgrade?
Please help
What about MAC-Telnet ?
I can’t even ping it or give it an address. Can you tell me how to Mac tel into it if I can’t talk to it. I have no experience doing that, but would gladly try.
Thanks
Connect your PC to RB750G, run Winbox, click button with three dots, wait few seconds.
Your RB750G should appear on list, click MAC address, not IP address, next click ‘Connect’ button.
HTH,
It’s connected with no sight. I clicked the three dots, it opened and waited. Nothing on the open page. I’ve reset the RB, used different ports, nothing. Thanks for the attempt. Hopefully something will let it be seen. What a waste just for an upgrade.
Try to reinstall RouterOS using Netinstall
http://wiki.mikrotik.com/wiki/Netinstall
HTH,
I tried this also. Nothing sees the Mac address all. I cannot see the device plugged into my network, like it won’t accept or acknologe it is there. I wish there was an external way to communicate with it using the reset, power and bottom reset. It would be great if the device could be told to downgrade externally.
Thanks for your help. I am lost
Hold the reset button while booting in a NetInstall configuration (NetInstall running, ether1 connected to machine running it, all host firewalls on that machine are disabled). The router should show up.
I tried netinstall 4.17 holding the reset button and releasing. It never popped up. I tried the same with winbox. Nothing. thanks for your attempt. I’m still holding hope that there will be a way to connect with the router. It won’t even work as a switch. It’s a brick.
It is rather unlikely it is proper bricked, but in my opinion we’ve exhausted all support options for the Internet. Try contacting your reseller, maybe they can help you out. If that does not get you anywhere try emailing support@mikrotik.com (yes, they will refer you to the reseller first, so do that before you even contact them).
Did you have static ip address set in windows while trying netinstall? Or did you release reset botton too fastly?
You have to set static ip address (eg. 192.168.1.11) for windows network card. Disable windows firewall. After that open netinstall and click netbooting-button to check that boot server is enabled and client ip is some ip address in same netwotk (eg. 192.168.1.4). Connect your pc to routerboard ethernet 1 port. Hold reset button while powering up routerboard until act-led stops flashing (about 10 seconds). Now your 750G should show up in netinstall. Then browse and select the package and click install.
I will give this a try today and report back. Thanks a million.
Have same problem after 5.0rc11 update. Nothing from mentioned instruction helped 
It worked for me thanks. Plug it into your laptop. Make the address for your laptop in the same as the netinstall boot and enable it. Hold the reset as you plug in and don’t let up on reset until activity light stops flashing. Exactly as the person stated above mine.
Thanks much. This forum rocks.
I did up the Karma of those that did my fix. Thanks again.
I have a 433 on a tower with the same problem. Do you have to hold reset pin?