why update eMMC?

If I plan to only boot to the SD card, why would I want/need to flash the eMMC with the latest?

This may be answered by the previous question’s answer; does flashing the eMMC update the
lowest level, stage 1, or whatever it’s called (whatever’s not in the DOS partition) u-boot code?
I guess I’m assuming that the lowest level boot code is u-boot, but perhaps that’s incorrect.

All boot files (MLO/u-boot.img) are visible in the fat partition.

It's just that the u-boot files get loaded from the eMMC first.

So the only reasons for flashing the eMMC, is to either use it, or to
update the boot files.

If you never use the eMMC, you can even "sudo dd if=/dev/zero
of=/dev/mmcblk1" and never worry about the eMMC's u-boot getting in the way


Yes, flashing the eMMC updates it's entire contents, including uBoot and
the "stage 1" loader. The first-stage loader is actually the MLO file
in the DOS partition (Memory LOader). MLO is a part of u-boot, and it's
job is to load the rest of uBoot into memory.

Great, thanks. I think it’s time to give my BBB a frontal lobotomy …

I wonder why the BBB has “only” 2G of space in the eMMC - aren’t most “small” boot images designed to fit in 4G? It’s great to have onboard bootable space, just seems like it would be bigger or why bother since many/most will just end up not using it and booting from flash.

Cost. That is what a $45 board allows us to buy. 4G is more expensive than 2G, And eMMC is faster and more reliable than an SD card.


eMMC controller on am335x is up to 4.3 and SD spec up 2 SD2.0, so . on this board .eMMC speed should faster than SD card

Just as an additional

On omap5 and iMX6 , and almost other recently SOC , they will support eMMC 4.4 and SD 3.0

eMMC 4.4 spec define 50M clock DDR mode and 8bit data ,bandwidth is 800Mbps

But SD3.0 spec define SD104 while clock up to 200M , so the bandwidth is also 800Mbps

use sd card benifit is easy to replace . and easy to upgrade .

Since I get a bricked samsung S3 , I feel so strong about sdcard rootfs is necessory .

My builroot rootfs, with QT, opencv, some boost libraries, python, a small webserver and other amenities uses only 10% of that 2GB.

I’m thinking to use Charles S’s MachineKit LinuxCNC image, which occupies 4G and would like to run it from the eMMC rather than an SD card, with card dedicated to machine/print job files.

I was a little annoyed (but happy) to hear that there’s a 4G revD board shipping soon, at least according to Sparkfun here:


Is this true? If so, is it a clone or original BBB revision? Why not mention plans for the new rev in either this or the “out of Stock” thread?

Anyway, happy it’s coming if true.

There is an announced Rev C: http://elinux.org/Beagleboard:BeagleBoneBlack#Board_Revisions_and_Changes

I don’t know anything about a Rev D. All I was told about was a Rev C.




That section talks about a price increase between USD 5 to USD 15 for the rev C version.
Has anything been decided? Mouser has increased the price from EUR 36 ($49) to EUR 48 ($66).
Let's hope that's $15 for manufacturing plus some reseller profit, instead of the other way around!

-- Bas

We have settled at this point on $10. That has not been implemented yet, but that is the plan. Still trying to get feedback from all of the distributors before we nail it down…


On the documentation like http://www.elinux.org/Beagleboard:BeagleBoneBlack#Revision_C_.28Pending.29 is there any chance I could talk you into putting dates instead of using terminology like “4-5 weeks” which leaves me searching for publication dates of the document?

Just a typo on my part. Think I might have been reading about omap versions or something. The Sparkfun link said rev C and so should I have.



Awesome, thanks Gerald.