[Buildroot] "BR2_TARGET_ROOTFS_INITRAMFS" with U-Boot?

[Baruch Siach]

Hi Jens,

On Fri, Mar 23, 2018 at 11:05:24AM +0100, Jens Maus wrote:
> I am currently developing a buildroot-driven system (for RaspberryPi HW) 
> which uses U-Boot together with BR2_TARGET_ROOTFS_CPIO and 
> BR2_TARGET_ROOTFS_CPIO_UIMAGE in buildroot to generate a zImage and initrd 
> file which I can then boot via
> 
> load mmc 0:1 ${kernel_addr_r} /zImage
> load mmc 0:1 ${ramdisk_addr_r} /initrd
> setenv bootargs „root=/dev/ram0“
> bootz ${kernel_addr_r} ${ramdisk_addr_r} ${fdt_addr}
> 
> in U-Boot. This works perfectly fine.
> 
> However, I am currently evaluating the possibilities to directly embed the 
> initramfs into the kernel by switching to BR2_TARGET_ROOTFS_INITRAMFS. But I 
> am not able to boot the generated zImage via
> 
> load mmc 0:1 ${kernel_addr_r} /zImage
> setenv bootargs „“
> bootz ${kernel_addr_r} - ${fdt_addr}
> 
> It simply hangs at „Starting kernel…“ 
> 
> Unfortunately I don’t have any idea why this kernel with the embedded 
> initramfs doesn’t boot at all? It doesn’t even output any kernel 
> information/debug on the console.
> 
> Any idea what might be wrong here or how I could debug the situation to get 
> that zImage booted?

Your bigger kernel image, or its boot-time decompressed image, might be 
overwriting the DT. See section 4b in Documentation/arm/Booting of the kernel 
source.

baruch

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