We've upgraded a few RB2011iLS-IN from the version they were shipped with (6.39?) to 6.43. We've had a few of these where after the upgrade, the router is non-responsive.
I tried to netinstall one of these and it boots into netinstall but after I install the software, the router doesn't boot properly. It seems to go into an infinite boot loop as all the lights can be seen flashing periodically.