Attempting to change boot params on Debian 4.19.94 Buster IoT image.

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mcp

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Oct 15, 2020, 2:26:18 PM10/15/20
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Just noticed that others have viewed my question in the BB Black section.  I might have posted in the wrong
area of the forum.  Re posting to hopefully get a few U-Boot experienced eyes on this -- not trying to flood the forum.
Let me know if there's a cleaner/preferred way to do this. Thanks.

On Monday, October 12, 2020 at 4:25:44 PM UTC-7, cpmcp...@rtisys.org wrote:

Just getting back into BBB world - working on a PRU project.  I need to reserve some DDR memory for use as an
extended PRU data buffer and have decided, while experimenting, to add " mem=384M memmap=128M$384M" to the
kernel command line.  I managed to get that working on an older Debian image, but have updated all my boards to
latest (probably latest -1 by now!) Debian IoT flasher.  I'm running on the BBB flash mem not the uSD card.

I have read that Debian things have changed a bit and everything is now contained in a single partition.  The only
uEnv.txt file I can find is in /boot.  I have changed the line that includes console speed params to include the above
parameters but, they do not show up in the /proc/cmdline display.  Similar changes on older kernels have worked - or
at least show up in the /proc/cmdline display after booting.  I have also renamed the bbb-uEnv.txt file in /  to
uEnv.txt and edited it as well.  But, no joy there either.

Most of the info I find after searching is from 2011 - 2014, so not sure if its of any relevance.  I've read through and
and followed instructions found in my new copy of "Exploring Beaglebone" (ver. 2, and, by the way, a great book
worth having!).  Have a better understanding of the whole U-Boot process; but still not working.

Could someone please
shed some light on the current (i.e. 2020) procedure for adding custom kernel parms to the Debian boot?  I'm trying to
stay as close to the off-the-shelf BBB releases as possible, but just can't seem to find the path down to the right place
in the boot process to get these additional parms in place.  Any help would be appreciated.

Cheers,
Chuck
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