[U-Boot] Mips, U-Boot and ramdisk

Robert Hodaszi mouse1 at sch.bme.hu
Mon Jun 22 16:55:30 CEST 2009


Can anybody help me? I'm working on this for a few days...

I'm working on a custom developed board, with Au1200, and I'd like to 
use the U-Boot as bootloader. I ported the U-Boot to my board, made a 
Linux kernel image, and a ramdisk image.

To try out the configuration, I burn the U-Boot image into the flash (it 
works well), and after I start the board, it download the kernel image 
and the ramdisk image through TFTP. I'm using the following two commands:

tftp 81000000 uImage
tftp 81FFFFC0 uRamdisk

I set the bootargs variable to: root=\dev\ram (I used: set bootargs 
But when I'm trying to start the Linux with the

bootm 81000000 81FFFFC0

the Linux can't find the ramdisk. It write out:

Initrd not found or empty - disabling initrd

But when I set its address into the bootargs (so the bootargs: 
root=/dev/ram rd_start=0x82000000 rd_size=0x191160), it works well; it 
successfully find the image, and can mount it.

How does the U-Boot pass the ramdisk information? It sets some kind of 
environment variables in the bootm.c. But it doesn't work for me. Why? 
(I could use the bootargs solution in this case, but I'm afraid, it 
can't pass other arguments too, like ethernet address, etc.)

Thanks in advance!

Best regards,
Robert Hodaszi

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