How to check burned CD (if cannot perform media check)
If you have burned the .iso to a CD or DVD already, and you are having problems with that CD / DVD, and if for some reason the media check option does not work for you, and you still wish to check the md5sum on the CD / DVD, then you can do the following (thanks to a contribution by our openSUSE user ken_yap):
To check the md5sum from a just burned dvd:
Ideally, one would just use
$ md5sum /dev/dvd
But trailing zero’s and nuls at the end can change the MD5 hash. So to calculate the md5sum we need to run isoinfo on the file to get the number of blocks. E.g.
isoinfo -i /dev/sr0 -d
Look for the line
Volume size is: XXXXXXX
Use this in a dd command:
dd if=/dev/sr0 of=image11.iso bs=2k count=XXXXXXX
It is possible that when you burnt it, you had some padding blocks. This will affect the md5sum if you read it off the DVD, but no contents should be affected even if get back more blocks than what you originally had in the download.