MacOS users BEWARE!!  I just bricked an A7RII ILCE-7RM2 trying to update from 4.0 to 4.01 using my MacBook Pro with Catalina 10.15.3 VERY CAREFULLY following Sony's instructions.  I had updated this camera with this computer but an earlier OS successfully in the past.  About 1/3 way done, the camera just disconnected from the computer (volume disappeared from desktop), the little red light would not go out, and the camera would not reconnect.  I tried pulling the battery.  I read where some folks had to run the update more than once, but I couldn't run it again on the Mac because the Mac would not mount the camera as a mass storage volume.  The reason I am not really upset is my wife has a desktop PC, and even in this messed up state, the camera responded to the Windows updater and is updated and running.

You're doing better than I am.  Trying to update 7RM2 from 4.00 to 4.01 here as well.  Could never get the updater / loader combo to recognize the camera even though the volume appeared on the desktop.  Tried via VMWare Fusion emulator on Mac with no luck either.  Headed to the PC and Windows 10 to see what happens . . .