Have you checked whether your drive requires -dd01 or -dd1 to switch the filtering to DD mode?
It can matter a lot for A2 disks and with the incorrect mode some dumps may end up unusable... what you need is to find the correct DD mode.
Short version: filtering specifically intended for HD disks does not tolerate flux reversal periods that are longer than what a HD MFM encoded data should contain, and turns up the AGC. This in turn introduces fake flux reversal signals, rendering the data read full of errors - there is no way to recover the real, DD flux reversals.
The density mode (-dd?) matters a lot on some drivers, not a big difference on others, and on some drives it does not work at all... so it's always a good idea to test first what works best on YOUR drive. (even different steppings of the same manufacturer/model might behave differently)