Well, the cool thing about the free Unices (and Linux)
is that you
can dig into the source code for dd and find out. And if it doesn't
put blank space where errors occur, you can modify it to do so.
Perhaps with a command-line switch option, if one doesn't already
exist.
dd conv=noerror,sync
/~\ The ASCII der Mouse
\ / Ribbon Campaign
X Against HTML mouse at rodents.montreal.qc.ca
/ \ Email! 7D C8 61 52 5D E7 2D 39 4E F1 31 3E E8 B3 27 4B