i faced the same issue, and went back on the eu forums to do a quick readup... its mentioned here in the first post on
stable releases that the rom zip file for sweet is a hybrid one, meaning that it can be flashed both via recovery as well as fastboot and as
@YuRuMii pointed out, there are 6 script files in the unzipped rom file...
fastboot_first_install_with_data_format
and
fastboot_update_rom
each for linux, macos and windows (batch files)
if i remember correctly, you can switch to fastboot mode and then either run the desired script (batch file if you're using windows) file either by simply double clicking it or theoretically it should work with the mi flash tool also, just select the desired script file from the bottom right drop down menu after selecting the unzipped folder of the rom (
although theoretically it should work, i haven't checked the mi-flash-tool method, therefore not sure)
if the above methods still haven't worked (which i think is the case for you) and the device incompatible message still shows up, you can open up the script file you chose in a text editor of your choice and just comment away the lines that check for the device id (those lines are there just to prevent the rom of one device, say sweet, being flashed on another device, say alioth), which should definitely work
for the windows batch script
windows_fastboot_first_install_with_data_format
for example, it should be the lines
Code:
for /f "tokens=2" %%D in ('%fastboot% getvar product 2^>^&1 ^| findstr /l /b /c:"product:"') do set device=%%D
if "%device%" neq "sweet" echo Compatible devices: sweet & echo Your device: %device% & pause & exit /B 1
make your own judgement calls as necessary if you're using any of the other scripts