Windows 10 does not see iPod Classic 6gen anymore

[Shants]

Hi everyone,
For years I happily used Rockbox on an iPod Classic 6th generation. Lately, when I connect the iPod by USB to any of 3 computers (which all run Windows 10), Windows assigns a drive letter, but freezes when I want to expand. Playing existing music and charging work fine, so I think this is more a Microsoft than an iPod issue. I noticed that in device manager there used to be a Rockbox driver, which is now a generic iPod driver.
I tried to get into the original Apple bootloader, and to reset the iPod into disk mode, but neither works. Rockbox version is 08199cd. Because Windows does not recognize the iPod, the Rockbox installer or recovery software do not work.

Does anyone have an idea how to fix this?
Best, Shants