OK, now Win10 hacked me off, really much.
And I'm not sure what MS is doing, but it doesn't look good.
Let's start from the beginning. My last Windows was XP, and I'm still using XP and 98 in some older machines (chip programmers won't work on newer systems), I have virtual machine with 7 at work to use when I really have to view CAD drawings made in TOMCAD and similar "deflated-deflated-deflated-...-deflated-coordinates" format (read: all CATIA-like). However, I bought a device with Win10 (GPD Win). What more, I decided to leave this rolling-release parody when installing Linux to install some games in the near future. The "near future" came and I decided to push a few old-good things there (OK, not too old, mid-2000s). Because after reading Win10 ToS I lost all motivation to connect this OS to my network, I decided to use USB flash drive for transferring games.
The only 8GB I had at the moment was the drive I used to set Debian up, with all these partitions needed for EFI boot. So i popped it to XP machine, formatted it in HP formatter and had one FAT32 partition. Put to GPD... no result.
Tested everything. Port is OK, this 512MB USB flash drive works. 8GB stick is OK, I even copied files on it in Linux, I re-formatted it in GParted, but Windows doesn't see it. I can even see it in GPD after re-booting to Linux. So, OK, let's go with Windows 10's disk management tool, I found the disk online in management applet, started to format... Cannot format because... the disk is offline! WTF?
After a quarter of two of futile tries to make this drive have a filesystem I decided to start from scratch using diskpart. Guess what - Cannot clear it because "the system cannot find the file specified"!. The answer in the Internet is to install... a fixed driver! We have XXI century, operating systems have USB storage drivers since more than a decade and they want me to install a driver? OK, I managed to download a fix from MS (quite difficult and requires fiddling with URL in an address bar), moved with 512MB stick, launched as admin...
Nope. I don't have Internet connection! Doesn't matter that it's not needed, that I can peek inside the fix and with some RE find a newer DLL there, it won't install without!
Linux at least may print to the console what's going wrong. It may be totally incomprehensible, but someone will understand the logs. Here's no explanation, just an error. And I was thinking that Linux is complicated.
Finally I moved 9GB using this 512MB drive, piece by piece. Installed, works. OK, only in windowed mode because in fullscreen it rotates the screen (interesting phenomenon: To the other side than BIOS/GRUB are rotated), but works, with Borderless even in emulated full-screen.
My feeling is that MS is doing with USB flash drives the same thing as they were doing with floppy drives in 2000s - in XP they destroyed the driver to the point that many totally OK disks, used in previous versions, started to be unusable, throwing false errors and informing about damages in places where there were no bad sectors. So what are they trying to push now, cloud services? And when they will emulate faults on our hard disks?