I upgraded RB433AH from v5.26 to v6.41.1, after the upgrade the RouterBoard kept rebooting. This also happened to SXT 5nD r2, I would like to know if there is any problem causing this and how it can be resolved? I will appreciate anyone help.
It is quite a big version jump. I would have updated to an early release 6 first, then maybe to 6.29 or so and then to 6.41.
For now, just netinstall the device. When it is a complicated config, try “keep configuration”. When not, configure it again from the defaults.
Yes that would be a safe procedure to update it in-place.
Now that it already has been “destroyed” you can netinstall it immediately to 6.42.1 and indeed upgrade routerboot as well.
The above procedure should be followed when you have other devices with such old software you want to update.
Netinstall process is not in any way affected by the RouterOS version installed on the router. Netinstall must work if it is properly configured, computer is not blocking it and up-to-date Netinstall version is used for each and every RouterBOARD as long as proper RouterBOOT is installed on the device.