Sometimes (actually quiet frequently) when I change channels it happens that the dreambox refuses to tune to certain channels. For example when I zap from RTL4 to RTL8 (CDS NL 19.2e) the box comes up with a 'tune failed' error. Sometimes it tunes after I wait a bit, sometimes I have to switch to another transponder/satellite and then back so it tunes again.
On other positions (13.0e, 23.5e and 28.2e) I have the same problem.
The problem exists with both the recent DMM and other images. A friend of mine has the same problems.

I changed the sat feeds from my DM7000 and DM500 to the DM7025 to rule out a cabling or other problem, but it seems that it is either a hardware or software problem. The problem persists on my DM7025 while the other boxes tune fine. Once tuned, the SNR, AGC and BER seem fine. ( 88%, 90% and 0 )

Working with different 4-to-1 DiSEqC switches (all setup the same) and quad LNBs, but it seems it is unrelated to which I use.