[Arm-netbook] A new MK802 failing to boot from SD

[lkcl luke]

On Sun, Jul 29, 2012 at 12:35 PM, Roman Mamedov <rm at romanrm.ru> wrote:
> On Sat, 28 Jul 2012 18:04:26 +0600
> Roman Mamedov <rm at romanrm.ru> wrote:
>
>> I can't get it to boot a custom kernel anymore (after like 15 attempts,
>> rebuilding kernels both with and without IGNORE_ATAG_MEM and various mem=
>> settings).
>> Maybe someone can point me to a howto about opening the MK802 and connecting
>> the serial console?
>
> I've connected the serial console using
> http://linux-sunxi.org/File:Mk802_uart.jpg
>
> I now have it successfully booting and working stable with my 3.0.38 kernel
> residing in the internal flash, with hardcoded kernel command line of
> "console=ttyS0,115200 root=/dev/mmcblk0p2 init=/init loglevel=8
> rootfstype=ext4 rootwait mem=448M at 0x40000000" and linux.ini pointing at this
> kernel so it's booted directly.

 eyy, well done!

> With this command-line only 448MB of RAM is accessible, but an attempt to also
> add "mem=512M at 0x60000000" results in boot-up indication of 960MB of RAM, but
> an attempt to access large amount of memory (e.g. with 'memtester') locks up
> the machine.

 ok, henrik knows a bit about this, and amery does as well: it's a
known issue.  something about the version of u-boot not reading the
size of the RAM properly, and not passing that on correctly, i don't
know the details.

 l.