8.5 firmware is sloooooow

[Coinneach]

I'm seeing the 8.5 firmware take up to 15 minutes just to get to the point where I select the updates to install. The "booting" screen alone takes up to 5 minutes, and enumerating the installed and available packages takes another 10. Then the actual installations take about twice as long as previous versions. This is regardless of model (my customer's DL385-G1s take just as long as their DL585-G2s). I've had to advise my customer to allow twice the usual downtime for firmware updates, which is unacceptable to them.

So. Known issue? Roll back to 8.4?