Hello,
I have the following problem with the upgrade to version 6.x ROS:
Configuration: RB411AH with fw 3.10, CM9 wlan, ROS version 5.25
When I do upgrade to 5.26 after reboot starts normally, but when I want to do an upgrade to version 6.x (6.4, 6.7, 6.10), ends with restart loop. Few times it happened that after the upgrade to version 6.x RB starts, but when I connect and log in using Winbox, I do not see any interface and any settings, just empty boxes (with ssh too).
When I make reset, RB with 6.x started. However, I get the configuration for versions 5.x to version 6.x? When I tried to replace RB, experiencing the same problem.
What routerboard?
RB411AH + CM9 + fw 3.10
First, update the bios.
Go to “system” “routerboard” click on “upgrade”

Hello,
As I wrote at the beginning, so there is the current firmware version 3.10 and RouterOS is 5.26.
When i make upgrade routeros to 6.x version, RB goes to infinite reboot loop

Try first to upgrade with netinstal
See this link for the procedure
http://www.wirelessinfo.be/index.php/mikrotik/pages/netinstalle
Than update the bios.
Let me know of it works please
Hello,
It was one of the first options that I tried.
But it does not help anything, when I will upgrade to version 6.x end up in a reboot loop