[Arm-netbook] microdesktop v1.7 arrived, works fine... but...

[doark at mail.com]

On  Thu, 6 Apr 2017 06:12:16 +0100
Luke Kenneth Casson Leighton <lkcl at lkcl.net> wrote:
> ok so the story goes like this:
> 
> back in august 2016 i got the A20 card up and running with mainline
> 4.7rc1 (or thereabouts), including patching in NAND support for a
> proper mtd device.  it worked... up to a point... except when u-boot
> did a complete scan it CORRUPTED the NAND flash... just from reads.
> 
> i figured this was "just software" as it's pretty experimental, and
> the 3.4.104 sunxi-nand works perfectly.
> 
> fast-foward to a few months ago, when i was testing the external
> micro-sd slot, weirdly it resulted in a kernel segfault *from the
> sunxi-nand driver*.  i thought, "that's weird, might be to do with
> current-fighting from the micro-desktop PCB not having level-shifting"
> 
> sooo... that's now fixed: the micro-sd slot works perfectly through
> the new revision 1.7 microdesktop's level-shifting IC.  however i got
> exactly the same kernel segfault in the sunxi-nand driver, so i
> temporarily took it out of the kernel config, tested again, and yes,
> the micro-sd worked fine.
> 
> ... except that when i booted it up again, the nand flash had been
> corrupted.  now, bear in mind there's *NO DRIVER INSTALLED*.
> 
> this is just too weird for me to deal with.  not to mention, because
> of the age of the A20's Boot ROM there is now a limited set of
> "legacy" NAND ICs available i've had it with them.
> 
<snip>

I'm sorry to hear you are having trouble.
Personally, I like the super weird Linux problems. Can I have one of
those malfunctioning alpha boards to try to figure out what's going on?
I grant you that I've never worked on something quite this low level
before, so I won't be solving it any time soon, but it would be worth
looking into just so that we don't have this problem again (yes, I would
like to learn how to create SBCs).

Thanks,
David