[U-Boot-Users] Ram disk image for ARM and CRC error in flash

[Swapnil Ashok Narkhede]

I want to get the OS image running
on pxa255.
I have several questions
1>
 TIll now i was just making 
OS image (uImage ) and loading it to
RAM and then to flash.
When i load the image to RAM and execute
iminfo 0xa0800000 i get the image info
with valid checksum.
o/p>>>
SWAP$ tftp 0xa0800000 uImage_gzip
Using MAC Address 00:04:34:00:21:59
TFTP from server 192.168.37.202; our IP address is 192.168.36.173
Filename 'uImage_gzip'.
Load address: 0xa0800000
Loading: T #T ################################################################
         #################################################################
         #####################
done
Bytes transferred = 771969 (bc781 hex)



SWAP$ iminfo 0xa0800000
## Checking Image at a0800000 ...
   Image Name:   Linux Kernel Image
   Image Type:   ARM Linux Kernel Image (gzip compressed)
   Data Size:    771905 Bytes = 753.8 kB
   Load Address: a0800000
   Entry Point:  a0800000
   Verifying Checksum ... OK
o/p<<<


After erasing the relevant  memory in
flash when i transfer 
the OS image to flash using 
cp.b 0xa0800000 0x40000 0xbc781(size)
i can tranfer the image successfully,
but when i do iminfo 0x40000 i get
the result as 
Verifying Checksum .. Bad DATA CRC.
the iminfo in both cases transfers
exactly the same size data, 

o/p>>>
SWAP$ erase 0x40000 0x1fffff
....... done
Erased 7 sectors

SWAP$ cp.b 0xa0800000 0x40000 0xbc781
Copy to Flash... done

SWAP$ iminfo 0x40000
## Checking Image at 00040000 ...
   Image Name:   Linux Kernel Image
   Image Type:   ARM Linux Kernel Image (gzip compressed)
   Data Size:    771905 Bytes = 753.8 kB
   Load Address: a0800000
   Entry Point:  a0800000
   Verifying Checksum ...    Bad Data CRC
o/p<<<

Why do i get this error.

2>
Using the uImage in RAM, when 
i try to execute it using bootm from
the RAM. i get the following output

o/p>>>
SWAP$ bootm 0xa0800000
## Booting image at a0800000 ...
   Image Name:   Linux Kernel Image
   Image Type:   ARM Linux Kernel Image (gzip compressed)
   Data Size:    771905 Bytes = 753.8 kB
   Load Address: a0800000
   Entry Point:  a0800000
   Verifying Checksum ... OK
   Uncompressing Kernel Image ... OK

 B4 starting kernel
Starting kernel ...


B4 cleanup
After cleanup
o/p<<<

I had just putup few printf statements to 
know exactly where the System hangs. It
hangs during the callto function
theKernel. Which receives the bootparams.

After reading the manual, REadme and  a  few posts
i came to know that the bootargs were set to NFSboot.
but the bootargs env variable was not properly
configured.
As per my understanding it is mandatory to either specify
root file system as INIT RAM DISK or NFS for the 
OS to boot. Is it?

3>
I would be able to prepare uRamdisk using mkimage,
but that requires an image data file
SIMPLE-ramdisk.image.gz to be specified with the
-d switch.
How do i make the SIMPLE-ramdisk.image.gz so that
i can make uRamdisk.
OR from where do i find SIMPLE-ramdisk.image. for
ARM processor


Regards,
Swapnil Narkhede
Mob:- 0432025023
Email:- s3092131 at student.rmit.edu.au
School of Computer Science and Information Technology
RMIT University, Melbourne