[FE training-materials-updates] kernel labs: simplify MMC boot instructions
Michael Opdenacker
michael.opdenacker at free-electrons.com
Sun Sep 22 18:31:56 CEST 2013
Repository : git://git.free-electrons.com/training-materials.git
On branch : kernel-ng
Link : http://git.free-electrons.com/training-materials/commit/?id=496a2388fa13f21a67a9fd0ec2752c73604090dd
>---------------------------------------------------------------
commit 496a2388fa13f21a67a9fd0ec2752c73604090dd
Author: Michael Opdenacker <michael.opdenacker at free-electrons.com>
Date: Sun Sep 22 18:29:33 2013 +0200
kernel labs: simplify MMC boot instructions
- Explain that holding the power switch button only needs to be
done once, when the power line is connected.
Signed-off-by: Michael Opdenacker <michael.opdenacker at free-electrons.com>
>---------------------------------------------------------------
496a2388fa13f21a67a9fd0ec2752c73604090dd
labs/kernel-board-setup/kernel-board-setup.tex | 44 +++++-------------------
1 file changed, 9 insertions(+), 35 deletions(-)
diff --git a/labs/kernel-board-setup/kernel-board-setup.tex b/labs/kernel-board-setup/kernel-board-setup.tex
index 0b263f1..e9cc515 100644
--- a/labs/kernel-board-setup/kernel-board-setup.tex
+++ b/labs/kernel-board-setup/kernel-board-setup.tex
@@ -80,33 +80,6 @@ other end of the cable).
See what messages you get on the serial line.
-\section{Disable booting from internal flash}
-
-If the board managed to boot to a Linux prompt, it means that
-it booted from its internal flash storage ({\em eMCC: Embedded MMC}).
-At least, that's want you get on brand new boards.
-
-As we want do boot from the external micro-SD card only,
-and do not want to have to hold the \code{boot switch} button \footnote{That's
-the button that's alone near the micro-SD slot} every time we're booting
-the board, we are going to disable booting from internal flash, by
-removing the \code{MLO} file in the boot partition:
-
-If you have a Linux prompt, you shoud be able to login in as \code{root}
-with an empty password. If your board didn't reach a Linux prompt, we
-will fix this later, and you can jump to the next section.
-
-Type the below commands:
-
-\begin{verbatim}
-mount /dev/mmcblk0p1 /mnt
-mv /mnt/MLO /mnt/MLO.orig
-umount /mnt/
-\end{verbatim}
-
-If you reset the board, you should now only see a sequence of \code{C}
-charaters.
-
\section{Prepare a bootable micro-SD card}
Using a micro-SD card is a convenient way to control the way
@@ -168,8 +141,15 @@ sudo umount /media/boot
\section{Boot the board}
-Reset the board (using the tiny reset button close to the Ethernet
-connector). You should then see U-boot 2013.10-rc3 start.
+Force the board to boot on the external card. To do this, you will
+have to remove the power supply, press and hold the \code{boot switch}
+button, insert the power supply, and then release this button.
+
+Note that from now on, the board will always boot on the external
+MMC, until you remove the power. You only have do this manipulation
+when you power on the board for the first time.
+
+You should then see U-boot 2013.10-rc3 start.
Press a key in the \code{picocom} terminal to stop the U-boot
countdown. You should then see the U-Boot prompt:
@@ -177,12 +157,6 @@ countdown. You should then see the U-Boot prompt:
U-Boot>
\end{verbatim}
-If this didn't work, it's probably because there is still a valid
-\code{MLO} on the internal MMC. To force the board to boot on the
-external card, you will then have to remove the power supply, press and
-hold the \code{boot switch} button, insert the power supply, and then
-release this button.
-
You can now use U-Boot. Run the \code{help} command to see the available
commands.
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