Originally Posted by dlanor
I'm confused by your repeated reference to "+boot" as being the Dev2 partition. I have a DMS4pro myself, and it uses the Dev2 partition "__boot", and that is also the case for Dev2 as implemented for Matrix Infinity. I have never before heard of anyone trying to use "+boot", and I don't think that this can work with any available Dev2 firmware.
Secondly, I wouldn't rely on the ability of the Dev2 launcher of any mod-chip to launch MyPS2 correctly, as I know that it requires some special methods that may not be used by the mod-chip code (specifically "fakehost.irx").
You'll probably be better off starting some other launcher with Dev1/Dev2, and then use that to start MyPS2 from HDD. That has worked well for many others, including myself.
Best regards: dlanor