[bootlin/training-materials updates] master: Flash lab: make sure people don't use U-Boot from MMC (a6b086ec)

[Michael Opdenacker]

Repository : https://github.com/bootlin/training-materials
On branch  : master
Link       : https://github.com/bootlin/training-materials/commit/a6b086ec563a14d791ed4deb645cf8c1066a92bf

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commit a6b086ec563a14d791ed4deb645cf8c1066a92bf
Author: Michael Opdenacker <michael.opdenacker at bootlin.com>
Date:   Tue Oct 6 09:26:51 2020 +0200

    Flash lab: make sure people don't use U-Boot from MMC
    
    - Will need to investigate the issue
      With U-Boot build from the MMC configuration, U-Boot
      sees a subpage of 512 bytes (instead of 2048) on the Xplained board,
      and this is incompatible with what Linux sees. Hence U-Boot
      cannot use a UBI space that Linux can use.
    
    Signed-off-by: Michael Opdenacker <michael.opdenacker at bootlin.com>


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a6b086ec563a14d791ed4deb645cf8c1066a92bf
 labs/sysdev-flash-filesystems/sysdev-flash-filesystems.tex | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/labs/sysdev-flash-filesystems/sysdev-flash-filesystems.tex b/labs/sysdev-flash-filesystems/sysdev-flash-filesystems.tex
index 91ae78ad..91ea1f93 100644
--- a/labs/sysdev-flash-filesystems/sysdev-flash-filesystems.tex
+++ b/labs/sysdev-flash-filesystems/sysdev-flash-filesystems.tex
@@ -12,6 +12,11 @@ Stay in \code{$HOME/__SESSION_NAME__-labs/tinysystem}. Install the
 \code{mtd-utils} package, which will be useful to create UBIFS and
 UBI images.
 
+Also remove the SD card, to resume to the former way of booting.
+That's important because there is currently an issue with U-Boot
+compiled from the MMC configuration, which causes UBI incompatibilities
+between U-Boot and Linux.
+
 \section{Goals}
 
 Instead of using an external SD card as in the previous lab, we will