I have downloaded knoppix 7.4.2 and installed it on usb flash drive using the read only option. At that time I did not want persistence.

Now I need persistence. On earlier versions, knoppix would ask where to create knoppix-data.img if it did not find one in any of the root partitions.

This is not done in this version.

I tried to manually create an img file myself (using dd) and saved it in the root of my harddisk. However this is ignored at boot.

Am I missing something please? A boot flag maybe? Or has the name of the persistent image file changed? Or does it need it to be in a directory called KNOPPIX even when not on the pendrive?