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Re: Providing (armhf) u-boot images together with d-i images?

On 2015-01-02, Ian Campbell wrote:
> On Tue, 2014-12-30 at 13:42 -0800, Vagrant Cascadian wrote:
>> On 2014-12-30, Ian Campbell wrote:
>> I think the difference is one is a set of netboot images, and the other
>> is a set of hd-media images.
> But what is the difference between these two things in this context?
> Aren't they functionally identical from the users perspective?

Differnt initrd with different modules, and defaults to loading a
different set of udebs. The hd-media scans for .iso files, the netboot
initrd requires to download remaining udebs using network...

Technically, both images could be made to do either based on bootprompt
options or something, but that probably would require rewriting a bit
more of d-i.

> pxelinux.cfg stanzas can include an "fdtdir" directory which is a path
> which u-boot will search for ${fdtfile} under.
> This isn't terribly well documented, but
> http://patchwork.ozlabs.org/patch/423507/ improves things a lot.

Thats really helpful, thanks!

> Speaking of which, does the extlinux.conf stuff (which also supports
> fdtdir) help with the multiple images problem at all?
> extlinux.conf (and pxelinux.conf) also has the advantage over boot.scr
> that it can offer multiple options (graphical vs text etc etc).

I don't think so, as netboot/hd-media are different images entirely. I
guess you could conceptually make one image with both initrds, and you
could use the menu support to select between the initrds... not sure if
that's worth doing at the moment.

>> I also think more systems support booting boot scripts than u-boot's
>> "PXE" emulation at this point.
> That's true.
> Going forward we should try and make it our default option though I
> think -- it was basically put together this way by the Fedora guys to
> support exactly this sort of scenario.

Seems reasonable. I'll add it to the increasing list of features I want
to get into u-boot for Jessie+1...

>> 1 u-boot only for each supported platform
>> 2 hd-media full with u-boot + kernel + initrd + dtbs + bootscript for
>>   each platform
>> 3 hd-media concatenateable with kernel + initrd + dtbs + bootscript
>> 4 netboot full with u-boot + kernel + initrd + dtbs + bootscript for
>>   each platform (like mini.iso)
>> 5 netboot concatenateable with kernel + initrd + dtbs + bootscript
>> 6 netboot boot script for use with TFTP
> (I've switched your bullets to numbers for ease of reference).
> Are 2+4 and 3+5 not essentially the same things with different names (on
> x86 the distinction is iso image vs a f/s image, but on ARM both are
> sd-card images).

They're both typically used with sd-card, yes. But they differ in how
they load the remaining portions of the installer, and have different
modules and udebs in the initrds appropriate to the install
media. Hopefully that's clear now? :)

live well,

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