Hi guys.
I apologize if my post duplicates another one - I used search but could not find a suitable answer to this question here.

My problem is as follows:
I have installed about 100 small HOT SPOTs based on RB750. At the date of installation, firmware was 3.29. Everything is configured and works well.
At one point, several failures occur and need replacing with some new RB750. The new RB750 comes with version 4.17 (I'm not so sure ).
Download and install 4.17 (or 5.9). Everything goes fine, reboot and RB750 works well.

The problem - after submitting the backup configuration (made in 3.29) RB750 lost any possibility of communication. No Winbox, no ping - nothing.
Until I press for a while the RESET button. After that with default configuration, RB750 work again.

Do you have any idea what might be the cause and how to fix it (though I still have 90 devices that can be damaged any time).

Best Regards
Mario

My suggestions
1. Try to downgrade to ROS version in which backup was made, and restore backup (in this particular case)
2. If your backup was taken from still working routerboard but with problems in its NAND/FLASH? memory, it will contain errors and become unusable anyway (that happened to me once)
3. Keep all remaining routerboards routerOS up to date if there are no reason why stick with older version (firmware i a bit different thing - see /system routerboard print , its related to board itself like bios on motherboard)
4. use some simple backup system or let routers send a email with rsc export instead of binary backup
- or use some simple automatic backup utility like this http://www.nbson.com/mtbackup/ so you don't need to care about ROS versions and you'll be able to reconstruct any mikrotik device from script even on different board or platform.

I don't think the 750's will work with 3.29 (I don't remember when they were released by almost completely sure 3.x was end of life when they were first produced). This means you are trying to restore a backup on a different hardware platform than what it was taken. This will make at the very least a partially broken configuration, and at worst in your case, evidently a completely broken one.

The better option would be to run a /export and edit the text areas that are router specific and then copy that text in. Keep in mind however that syntax has changed so not every setting will copy in right, you'll have to look at the lines that have errors and correct them.

You'll likely have to use netinstall to restore the 750 to factory defaults.

Hi man ,

I will give you a favor if backup/restore do not work,

export your configuration for example if you want to export the NATS do the following : /ip firewall nat export