I've never tried it, but I think you can tell grub to boot something only once. This way you can boot windows and then reboot to linux.
Something like this I guess:
When you are in linux, if you type:
You tell to grub to keep in mind that the saved default is windows.
After rebooting, since it executes the windows entry, it saves 0 as the default, so it will boot linux next time. So, every time you want to boot to windows type
in the linux terminal.
I 'll tell you again, never tried it but I cannot think of why this shouldn't work.
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