[U-Boot] "uEnv.txt" versus "fw_setenv" -- a question about style

[Robert P. J. Day]

  curious about peoples' preferences when it comes to customizing
u-boot on a running system -- using a "uEnv.txt" file that can be
trivially edited from user space, as opposed to using the u-boot
firmware tools to change the actual environment variables in
persistent storage.

  this is based on something else i will ask about later --
suggestions for target disk layouts that incorporate dual (active and
inactive) partitions for robustness and fallback in case of emergency.
but for now, let's keep it simple.

  obviously, i can certainly combine the two approaches above, but
because of the upcoming issue regarding robustness, i'm leaning
towards the uEnv.txt approach, and here's why.

  if i support updating the env vars in persistent storage, and a
system in the field suddenly stops booting properly, then i might be
completely in the dark as to what's in the u-boot environment. how do
i know what the user has been doing, or what variables he might have
changed? however, if i keep all the changes in uEnv.txt, it's easy to
get a look at that file and, also, simply removing that file
effectively sets the machine back to "factory defaults."

  in addition, if i have filesystem corruption that wipes out
uEnv.txt (among other things), then, again, i have effectively reduced
the system back to factory defaults so it can boot to a known good
state of some kind.

  i guess i'm more comfortable with the idea of a system having a
solid and tested u-boot environment that rarely (if ever) changes,
rather than regularly changing things in the persistent storage, but
i'm open to being persuaded otherwise; i'm just curious about what
others prefer.

rday

-- 

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Robert P. J. Day                                 Ottawa, Ontario, CANADA
                        http://crashcourse.ca

Twitter:                                       http://twitter.com/rpjday
LinkedIn:                               http://ca.linkedin.com/in/rpjday
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