There is a generic boot menu guide now here on the wiki.

For Froyo make sure you have the most recent release image and or build your own image.

Make sure:

• the image name matches the menu entry.
• the path to the image in the menu entry does NOT end in gz.
• if the name of your menu entry (from the start of the line to the first "|") does NOT contain the keywords "Froyo" or "Android" you have to add a "|0" to the end of that line.

Examples:

openAOS FroYo|/dev/sda1|/openaos-froyo-alpha5.img|/init

MyDroid|/dev/sda1|/my-froyo-build.img|/init|0

Please notice how the second example requires the trailing 0 to activate the  framebuffer setup for Android.