Many people tell about fastboot that it can be used to flash a image on one of the partitions.
Is the reverse also possible, that is take a binary snapshot and store it as a zip file containig the exact binary representation of the partition to be backuped?
the reason I ask this is
backup has two steps.
1) take and image/snapshot to backuplocation (backup)
2) and replacing image/snapshop from backuplocaito (restore)
to me it seems that fastboot is only doing one, while being able to write to the Androids internal flash (in binary "dd"-style) seems it should also be able to read from the flash.
This way nobody would need to organize and run another potentially not trustworthy rom to do the reading job.