I am looking for the fastest method of getting a new image that I've
compiled on the laptop into the beagle's RAM. All the methods I've
been able to find for transferring a new image to ram via Uboot use a
serial connection. It's so slow though, I think I can transfer the
image to an SD card and move it faster manually. Is there a fast
method that I am overlooking? I have a method for USB boot set up
over the OTG port, but that too is only serial. The new image is
baremetal, not a Linux kernel.
I have used a serial speed of 1Mbit/s in the past to upload kernel
images (~1MB) in a similar scenario. FTDI usb2serial dongles can
do 1Mbit/s easily and so can the omap3
you could also flash a "fastboot" enabled uboot into nand/sdcard,
that will allow you to upload even faster over usb OTG. The
pandaboard uboot has that, should not be hard to port it to
beagle since the musb part is most likely the same.
if you own a pre-xM (eg. c4) Beagleboard, here is one method I used for the same purpose:
* have a very minimal linux kernel configured as a USB mass storage dongle. Store the kernel into NAND, and make it boot automatically. When booted, the SD appears on your workstation as USB disk and you can transfer your bare-metal code very fast.
* Then you reboot with the user button pressed, which boots the OMAP from SDCard (your SDcard may require to be prepared with MLO and u-boot, see recovery instructions).
You could as well try to get a USB enabled u-boot. To be honest I am not sure that it really works (maybe someone here will give more detailled feedback).
If you own a -xM (without NAND), you can do a similar dual boot scheme, but it won't be fully automatic. I assume you will be required to launch either scenario by typing commands on u-boot prompt.