Hi I try to upgrade soft of this model from 3.29 to 4.2 and i do all with instructions (eg. upgrade help) When i push combined package to winbox, i see uploading complete, but when i reboot mt all ethernet port not working(all led are off). In this model no com port, and i can’t reset or look on log. Any idea how to reset (push button not reset when i pushed and plug in power) or make comunication on?
all leds are off mean no power. is your power supply working? try another one maybe. anything within the 12-28v range and plug should work
Power is ok(oryginal power suply)but still no communication on any port. LED from lan blinking couple times and no active. LED from power is ok. I have no idea how to resolve this problem without other communication port (e.g. com or reset to factory default) Can You help me?
Did u fix this it’s anoying when reeder won’t work
- Try to reset the configuration.
- Hold on Reset button;
- power on the RouterBOARD;
- wait until ACT link will start to blink, release reset;
- access the RouterBOARD
Second option to try.
- Netinstall,
- run Netinstall on your computer,
http://wiki.mikrotik.com/wiki/Netinstall - Hold on Reset button;
- power on the RouterBOARD;
- wait until ACT link will start to blink, hold on reset;
- ACT LED should stop to blink, release the button;
- Etherboot should be enabled on the router.
Let us know if it helped you.
I just tired to update to 5.2. Now the modem won’t boot. My problem is when I hold down the reset button and power on my act light doesn’t flash at all, no matter how long i hold the rest button down for. Any ideas
Guys, I had same problem, but could not find solution to that issue than forget about the rb750, i.e. discarded it and configure x86 system.
You will not be able to fix that problem… cus i had same problem and no one is able to assist.
Before RouterOS upgrade you should update the bootloader - type /system routerboard upgrade in the Winbox terminal window or telnet session, then press Y and restart the device. Possibly, you’ve bricked your routers because of an old bootloader…
Thanks for the help ElectricCat, I had a rb750g firmware 4.16, bootloader 2.xx (no the last one) I did an upgrade following http://wiki.mikrotik.com/wiki/Upgrading_RouterOS#Using_Winbox instructions, then rebooted and my routerboard stopped responding to winbox and telnet. I thought I bricked it!
I have to netinstall my 4.16 version, so I could user winbox again. Then I did what you told about /system routerboard upgrade, and having the last bootloader installed, I could do the upgrade from http://wiki.mikrotik.com/wiki/Upgrading_RouterOS#Using_Winbox, rebooted and happy now 
It would be great to have this as a sticky or warning somewhere (or maybe I missed it)
i had same problem plz soul my problam…
hi. visit this link. This problem fixed. work 100%
https://blog.ligos.net/2016-12-27/Recover-A-Broken-Mikroik-Device.html
I got a message today „MikroTik: URGENT security advisory“ where notice me „Since all RouterOS devices offer free upgrades with just two clicks, we urge you to upgrade your devices with the “Check for updates” button, if you haven’t done so already.“ what I did immediately, given that I understand very serious Mikrotik notices and I follow the advice that they give. Although on vacation I immediately started updating devices and on the first rb-750 I noticed a problem. And now I can not believe that I have to return 750 kilometers back to office to directly approach the device and fix the problem. I think this is a huge failure of the Mikrotik, I can not say that I am very disappointed by the ruined vacation and the additional costs