First of all, please let me apologize because perhaps this is not the proper section.
Let me explain my trouble: on a brand new RB450 arrived with ROS 4.11, I tried to upgrade with 5.5.
The action was performed via winbox (drag and drop) the npk file and subsequently reboot.
Other times, this procedure went ok but not this time.
From that moment the RB450 doesn’t bootstrap correctly.
Via Consolle I tried to upload the npk file. The file is transferred correctly but rebooting the problem remain the same.
With netinstall, the program doesn’t see the RB450 and the procedure doesn’t arrive at the end.
What to do ?
Via RS232 it is possible to arrive at the start menu but nothing else and RB450 continue to reboot because don’t find the kernel.
Any tips, suggestion more than to buy a new one ? Any help ? 
