have you typed boot or mac-boot?
Because I've seen that your bootcommand is set to mac-boot in your environment-variables.
It seems that mac-boot alway tries to boot the mac-partition.

So set in OF boot-command to boot:

setenv boot-command boot (you may always switch back by reset-all)

Your boot-device env-variable is set to search for MAC-tbxi - this could be a problem, you can set boot-device to hd:,\
setenv boot-device hd:,\

and now try boot hd:,\boot.img BD=MorphOS again.

The devalias for HD seems to be set propper in OF

But what happens with dir-command? Does dir hd:\ anything? If not, your HD isn't found........
Did you see your HD when running diagnostic-CD? Should be listed in hardwareprofile with vendor-name or unknown.
In case of "no media present" your HDs or cables may cause your problems. Are the powerlines OK and do the drives rotate?