If you use FMCB:
Did you press&hold the circle-button on reset, before the FMCB-Logo appears?
If not, try it this way and than start ule the way you normaly did (when the logo appears, just release the button. If you start ule with Button-Launch, than hold the button, while the FMCB-Logo is shown.).
If you use the DEV.1/2-Mode:
That will not work (most probably).
DMS needs to be launched in PSX-Mode.
@dlanor: I think, that suggestion about "BootDisc", that can start the internal "AudioCD-Player" isn't that bad.
So you want to implement it for "AudioCD", DVD-Video and ESR-Disc also. Got it right?
PS2 V7/DMS3 V2 (FW:2.4b7); Seagate Baracuda 200GB
PS2 V7/CC1.0 (FW:34 hacked v2 BM:2.1.6); Maxtor DiamondMAX9 PLUS 160GB
PS2 SCPH-30004R; NoMod+NoLaser
3xSony MC 8MB
MAX/Datel 16MB with Boot-CD
Custom FMCB 1.8b+ Beta-Build, my AIO 0.5, Sony&xRhino-Linux