Rom "locked Bootloader"

[BjornS]

Hello,

first of all xiaomi.eu thx and congratulations with your great ROMS!

I have a question about the roms.
What does it mean that at some roms it says "locked bootloader"? You have to unlock the bootloader to be able to install the ROM, so I don't understand.
I have now like suggested the twrp recovery and your ROM.
I would like to lock the rom again, but that is not recommended.
I tried the mi flash tool (for the clean and relock), but it doesn't work with the ROM's from here.
And I can only find complete roms so it looks like there is no way to relock the phone with a rom from here.
So that is also why I wunder why it says "locked bootloader" in the rom table.

Can somebody explain?

Thanks