I can not update my MBA from Yosemite OS.
I installed Big SUr but it crashed my Mac Book Air (Early 2014). I reseted my system back to Yosemite and cleaned the disk but now I can not register on iCloud neither instal a newer version of iOSx.
I downloaded all upgrades but they want start (for all .dmg files the messages corrupt image).
For El Capitain i got the message 'not compatible'
Is there any help?
MacBook Air 13″, macOS 11.0