Xiaomi may have a patchy history of providing kernel source codes but the company's bootloader unlock policies have always been fair—at least compared to that of other OEMs. Until last week, that is, when the Chinese company decided to stir up the muddy waters.
https://www.notebookcheck.net/Xiaomi-puts-users-through-the-ringer-in-bootloader-unlock-merry-go-round.328580.0.html