[bootlin/training-materials updates] master: slides/sysdev-bootloaders-u-boot: improve "Installing U-Boot" slide (04fc94ba)
Michael Opdenacker
michael.opdenacker at bootlin.com
Wed Feb 1 15:36:53 CET 2023
Repository : https://github.com/bootlin/training-materials
On branch : master
Link : https://github.com/bootlin/training-materials/commit/04fc94bacecb2e2ea1c63b463cb416e8dc620a05
>---------------------------------------------------------------
commit 04fc94bacecb2e2ea1c63b463cb416e8dc620a05
Author: Michael Opdenacker <michael.opdenacker at bootlin.com>
Date: Wed Feb 1 15:36:53 2023 +0100
slides/sysdev-bootloaders-u-boot: improve "Installing U-Boot" slide
Felt awkward not to clearly mention we're talking about
internal storage. This slide comes from the old days when
you could brick a board by breaking its bootloader, and
couldn't recover by booting on external storage.
We could even remove this slide.
Signed-off-by: Michael Opdenacker <michael.opdenacker at bootlin.com>
>---------------------------------------------------------------
04fc94bacecb2e2ea1c63b463cb416e8dc620a05
.../sysdev-bootloaders-u-boot.tex | 16 ++++++++--------
1 file changed, 8 insertions(+), 8 deletions(-)
diff --git a/slides/sysdev-bootloaders-u-boot/sysdev-bootloaders-u-boot.tex b/slides/sysdev-bootloaders-u-boot/sysdev-bootloaders-u-boot.tex
index 73690d0e..f9acf7b7 100644
--- a/slides/sysdev-bootloaders-u-boot/sysdev-bootloaders-u-boot.tex
+++ b/slides/sysdev-bootloaders-u-boot/sysdev-bootloaders-u-boot.tex
@@ -219,22 +219,22 @@ $ make DEVICE_TREE=am335x-boneblack-wireless CROSS_COMPILE=arm-linux-
\end{itemize}
\end{frame}
-\begin{frame}{Installing U-Boot}
+\begin{frame}{Installing U-Boot in flash (NAND or eMMC)}
Different possibilities depending on the hardware:
\begin{enumerate}
\item The ROM code provides some kind of specific boot monitor with
which you can communicate through the serial port or USB using a
- specific protocol
+ specific protocol, to flash U-Boot.
\item The CPU boots first on removable media (SD card) before
- booting from fixed media (NAND, eMMC). In this case, boot from
- removable media to reflash a new version
+ booting from fixed media. In this case, boot from
+ removable media to reflash a new version.
\item U-Boot is already installed, and can be used to flash a new
- version of U-Boot. However, be careful: if the new version of
- U-Boot doesn't work, the board is unusable
+ version of itself. If the new version of U-Boot doesn't work,
+ you will have to reflash it through another method (it is always
+ possible through an external SD card).
\item The board provides a JTAG interface, which allows to write to
the flash memory remotely, without any system running on the
- board. It also allows to rescue a board if the bootloader doesn't
- work.
+ board.
\end{enumerate}
\end{frame}
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