step-by-step (might help others too)
1 - Hold down Key1(Play/pause sign) and POWERON
This puts you in DFU mode and gives you a removable DFU disk on Windows platform
2 - Copy the .ADR file to the DFU disk
the DSO will disconnect and re-connect on USB
If you check the DFU disk directory, it will now show the .ADR file has now become .rdy or .not
if it is .rdy, your ADR file has been successfully read
.not means the file was not taken by dso
3 - If you got the .rdy confirmation in the previous step, copy the .BIN file to the DSO
Again you will find the DSO disconnects and reconnects
if you get the .RDY in the dfu disk, your file has been successfully copied.
if you get .not, the file is possibly bad
4 - Now POWEROFF the dso and POWERON
5 - Good to go now.!!
Maybe you missed some step??