For the Efika MX without the development board (serial interface).

I'm familiar with Grub as a boot loader in Gentoo. With Grub, you can be presented a menu screen to select which kernel to load. This is very handy when you want to try new kernels and select one you know that will return you to a safe environment when a new one fails.

Is there a way in U-Boot to display a dialog at the early stage to designate which loader script or kernel to install? I suspect not given my limited experience with U-Boot on the SheevaPlug, but I thought I pose the question here. I'm wondering if testing of kernels is possible without having to reboot form the SD card or have the development board so events at the outset of U-Boot can be monitored and interrupted.

indeed it's possible. E.g. there is a second stage bootloader[1] written by Cjg (a CRUX PPC developer) for Acube Sam440/Sam460 PowerPC boards that use U-Boot.

[1] http://cruxppc.org/viewvc/opt/branches/2.7/parthenope/

Oh wow, I had never heard of this. Have you actually used it on an EfikaMX? Seems interesting! (Things like this should definitely be brought to our attention!)

Alternatively (it needs a bit more work) there has been some work done on mainline uboot to get video support working. This should work right now, but it isn't in the main uboot tree just yet.