Re: Modifying kernel bootargs
On Fri, 2015-09-04 at 09:19 +0100, Tim Fletcher wrote:
> On 03/09/15 17:56, Ian Campbell wrote:
> > On Thu, 2015-09-03 at 18:00 +0200, JM wrote:
> > > Hi,
> > >
> > > I can't seem to figure out how to pass kernel parameters using flash
> > > -kernel. This is with flash-kernel 3.45 and linux-image-kirkwood
> > > 4.1.0-2
> > > from testing on QNAP TS-212P.
> > >
> > > I edit the LINUX_KERNEL_CMDLINE in /etc/default/flash-kernel, rebuild
> > > the
> > > kernel and initramfs image, reflash and... nothing. The command line
> > > in
> > > dmesg remains unchanged.
> > >
> > > Does this require some specific uboot version? Platform support? Is
> > > this
> > > currently working for other people?
> >
> > It needs platform support, specifically it only works with systems
> > which
> > boot via the /boot/boot.scr mechanism.
> >
> > On a QNAP system the command line is in the firmware I'm afraid. If you
> > have serial you can fiddle it from the u-boot prompt (I expect, I've
> > not
> > actually tried on this platform).
> >
> > Depending what your goal is you might be able to fiddle it in the
> > initramfs
> > without actually changing the cmdline, like /usr/share/initramfs
> > -tools/hooks/flash_kernel_set_root does for the root filesystem. That's
> > very dependent on what you are trying to go.
>
> I thought there was a way in flash-kernel
AFAIK only the root= which gets mounted not the command line in general.
> or mkinitramfs
I don't know about this for sure. I'm not aware of it if it exists.
I'm not aware of a mechanism for anything userspace (which is what
initramfs) to modify the command line, even if it is only halfway through
boot it's hard to know what that would mean.
> to override the bootloaders kernel args?
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