====== FAQ ======

==== U-Boot: "set read bl len failed" on access to SD card ====
=> After being plugged in the sd card must be initialised prior to any access. The command <code>mmc rescan 1</code> does that.

==== U-Boot: Usage messages for the command "setenv" ====
U-Boot prints the following error message at boot time: 
<code>
setenv - set environment variables

Usage:
setenv name value ...
    - set environment variable 'name' to 'value ...'
setenv name
    - delete environment variable 'name'
</code>
=> Amongst others a reason for this is that the U-Boot environment variable //bootargs// has been accidentally stored in the flash environment and already contains a value. The error occurs because the final value (string) to be stored in this variable eventually becomes too long.

To remedy just clear the variable //bootargs// und save the environment to flash:

<code>
setenv bootargs
saveenv
</code>