Hello, Le 05/09/2021 à 18:47, J. William Campbell a écrit :
AFAIK, the on disk format for ext4 is the same as ext2. If the code can read an ext2 filesystem, it can read an ext4 filesystem.
I am not sure about that. AFAIK, some ext4 features such as extents create a different on-disk format than ext2 or ext3. The ext2, ext3 and ext4 Linux drivers refuse to mount an ext4 filesystem as ext2 because of unsupported features.
older u-boots didn't know about ext4, so when they check the version of the filesystem they see a number that they don't understand and give up.
IIUC, an ext* filesystem does not have a version number. Instead it has a collection of "features", some of which are supported only by ext4.
But IMO the real point is : if ext2 is mandatory for /boot when installing with LVM, why then is it not mandatory when installing without LVM ?
