This update is a hot steaming mess! I just lost every cue point in my collection after starting fresh and re-analyzing everything. This is garbage!
You can obtain previous versions of the firmware from the Engine download pages.
Jut an FYI. It will not allow you to downgrade via usb. You have to do it by pc or mac connection.
Fully understand, ive had to do it before myself. It’s not an issue though.
What? Never downgraded. But can anyone tell me why it is not possible over usb?
I saved every version as a backup for USB…
Oh, you’ll love this. it won’t let me install 2.4 on my pc. it “installs” but does not show up.
Here is a link to another thread with a guide on how to downgrade.
I got that going, but now the software won’t install properly. I uninstalled and now i can’t get 2.4 to show up. i ‘install’ it, but there is no folder/icon or anything.
You made sure it’s on the root folder of the USB stick? It has to be on there or it won’t work, and the format has to be as instructed on that guide. The Apple format won’t work, has to be ExFat.
Perhaps you can try to do a system restore from your PC from an earlier backup / restore point? Check under your system restore points to see if there is a restore point dated like a day or so before you did the update. Worth a try… 
That is exactly what I had to do! It was crazy how nothing else worked.