[U-Boot-Users] Fail Safe: Redundant U-boot Images in Flash??? ?

[Frank]

--- "Eisenhut, Daniel (GE Healthcare)"
<Daniel.Eisenhut at med.ge.com> wrote:

> > > The code at the entry point needs to be small, reliable
> and never require an
> > > upgrade in the field. This code would run a CRC on the
> primary U-boot image
> >
> > THe code at the  entry  point  that  is  small,  reliable 
> and  never
> > requires  an upgrade in the field is U-Boot. Just don't
> touch it. You
> > don't have to.
> 
> ...insert bullet, spin cylinder, point at foot, pull
> trigger...
> 
> Hopefully, we will never need to update.  But if we do, it'd
> be nice
> to be able to reduce the risk of updating as much as possible.
> 
> > What you typically do (assuming the hardware supports it) is
> to  have
> > two  banks  of  flash memory that can be swapped using some
> jumper or
> > switch or so.
> 
> When it costs a grand just to have a service tech walk in the
> door, this
> becomes an unacceptable option.

What you guys are trying to do, I've done many times before. You
should at least have a bit mask in nonvolatile memory somewhere
that tells you the result of your operation. One bit tells the
the "miniboot'" loader That this is the first time the image has
beeen booted. Another bit is set when the new image comes up
telling the miniboot loader that it came up ok. If the new image
nerver get's to the point where it can set that bit and the
"first time bit" is reset then the miniboot loader won't try and
boot that image the second time around. I may have left some
details out but basically it works for me...
> 
> 
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