[U-Boot] saveenv on qemu vexpress-a9 flash problem

Yonghao Wang wyonghao at gmail.com
Fri Jun 23 20:04:14 UTC 2017


Hello,
For learning and education purposes, I am trying to use qemu-arm to
run u-boot. After reading online materials, my question is that if it
is possible to save the environment variables on simulated Flash
"permanently". I use raw file "pflash0.img" as simulated flash. So
far, after modify some #defines in the header file, now I can run the
following:

" qemu-system-arm -M vexpress-a9 -kernel u-boot -m 512M -nographic
-drive file=pflash0.img,format=raw,if=pflash  "

u-boot boots ok, and I can save the env variables. It takes effects
after "reset" u-boot. However, the values does not get written into
the flash image file. So next time I run qemu using same "pflash0.img"
file. The environment variables get lost. you will have "bad CRC"
message again.

I have these two questions:

1. Is it possible to save the environment variables to qemu simulated
flash file "permanently"?
2. u-boot seems only report the flash size that links to config header
files and does not link to the qemu simulated flash image size, that
is to say no matter how big or small I created the ""pflash0.img"
file, uboot only reports 128MiB flash.

Maybe I am doing something very stupid here. Please anybody can give
some suggestions.

Thank you all!

-- 
Yonghao (Leo) Wang


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