[LinuxBIOS] Checking if FlashROM pin A18 is connected?

[Leon Woestenberg]

Hello,

I have a 512 kByte FlashROM but use 256 kByte images so far. I 
concatenate two of them, so even if address pin A18 is dangling, the CPU 
reads the image correctly.

Now, if I understand correctly, the util/flashrom utility writes (-w) 
using the Flash programming algorithms, which do not touch A18. And if I 
understand correctly, it used
mmap() to verify the image, which should use A18.

Am I correct that by following this procedure, I can find out whether 
A18 is connected on my motherboard to the FlashROM socket? :

dd if=/dev/random of=/tmp/random.bin bs=1024 count=512

flashrom -w /tmp/random.bin
flashrom -v tmp/random.bin

VERIFIED => A18 is connected

Regards,

Leon.

*do not do this at home, it destroys your BIOS*

[Ronald G Minnich]

Leon Woestenberg wrote:
> Hello,
>
> I have a 512 kByte FlashROM but use 256 kByte images so far. I 
> concatenate two of them, so even if address pin A18 is dangling, the CPU 
> reads the image correctly.
>
> Now, if I understand correctly, the util/flashrom utility writes (-w) 
> using the Flash programming algorithms, which do not touch A18. And if I 
> understand correctly, it used
> mmap() to verify the image, which should use A18.
>
> Am I correct that by following this procedure, I can find out whether 
> A18 is connected on my motherboard to the FlashROM socket? :
>
> dd if=/dev/random of=/tmp/random.bin bs=1024 count=512
>
> flashrom -w /tmp/random.bin
> flashrom -v tmp/random.bin
>
> VERIFIED => A18 is connected

yeah, that ought to work. For this purpose, just for my own sanity, I 
usually make the image a file of ascending 32-bit numbers. Then you can 
use flashrom -r to make sure the things look right, as well as your -v 
trick.

ron

[Stefan Reinauer]

* Leon Woestenberg  [060225 22:30]:
> Am I correct that by following this procedure, I can find out whether 
> A18 is connected on my motherboard to the FlashROM socket? :
>
> dd if=/dev/random of=/tmp/random.bin bs=1024 count=512
>
> flashrom -w /tmp/random.bin
> flashrom -v tmp/random.bin
>
> VERIFIED => A18 is connected

Yes. If the top half and the bottom half are different and both can be
read, the pin for the highest bit is connected correctly.

Stefan

[Leon Woestenberg]

Hello,

Ronald G Minnich wrote:
> Leon Woestenberg wrote:
> > dd if=/dev/random of=/tmp/random.bin bs=1024 count=512
> >
> > flashrom -w /tmp/random.bin
> > flashrom -v tmp/random.bin
> >
> > VERIFIED => A18 is connected
>
> yeah, that ought to work. For this purpose, just for my own sanity, I 
> usually make the image a file of ascending 32-bit numbers. Then you 
> can use flashrom -r to make sure the things look right, as well as 
> your -v trick.

Thanks. Just did this* and it seems that A18 is connected on my VIA 
EPIA-M10000.

Regards, Leon

*but instead of /dev/random I took a large vmlinuz file and truncated it 
at 512kBytes using dd. /dev/random was dead-slow (infunctional) on my 
EPIA. Maybe not enough entropy sources, dunno yet.