[Buildroot] Using a precompiled busybox toolchain as an external toolchain

Samuel Martin s.martin49 at gmail.com
Sun Dec 30 13:53:55 UTC 2012

Hi Willy, all,

Apologize for the late answer.

2012/12/30 Willy Lambert <lambert.willy at gmail.com>:
> 2012/12/18 Willy Lambert <lambert.willy at gmail.com>:
>> 2012/12/18 Thomas Petazzoni <thomas.petazzoni at free-electrons.com>:
>>> Dear Willy Lambert,
>>> On Tue, 18 Dec 2012 16:19:47 +0100, Willy Lambert wrote:
>>>> aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaah. To be honest an entry
>>>> in the manual to state this would be nice.
>>> Indeed. Feel free to submit a patch for the manual :-)
>> yes, but how ? Should I edit html files by and in the docs/manual folder ?
Please edit the manual from docs/manual, this is the reference now.
See http://buildroot.org/downloads/manual/manual.html#_the_documentation

>> I'm not at ease with git, so I will see during hollidays if I can do
>> something with it.
Well, from my experience, playing with git is the best way to learn it! :P
BTW, there is a lot of doc and so on around the web, e.g.:
- http://try.github.com/levels/1/challenges/1
- http://git-scm.com/documentation
- ...

Concerning patch posting to Buildroot, the online manual gathers the
few useful things, see:

Lastly, if you sneak around on the Buildroot IRC channel, there will
most likely be
someone who will be able to help you with git. ;-)

>>>> thanks, should I understand that I can't publish the buildroot
>>>> toolchain on another  PC without installing it at the __same__ place ?
> may I bump this, how should I edit documentation ?
I guess you're using a git view of BR, so please pull it and rebuild the manual:
make manual-clean manual

Few things related to this have been merged yesterday thanks to Thomas! ;-)

> I succeeded in creating the toolchain in "MY_TOOLCAHIN_PATH", but :
> _ if I do a make clean it disapear, so I suppose I have to change
> BR2_HOST_DIR back the default value after having creating the
> toolchain ?
> _ what's happening if I create several toolchain for several arch in
> the same "MY_TOOLCHAIN_PATH ? does they override or do they install
> nicely both in the same dir ?
> _ what is the path I have to give to buildroot ? "MY_TOOLCHAIN_PATH'
> or something like "MY_TOOLCHAIN_PATH'/usr/...
In the updated manual (the one you should have built; unfortunately
not online until the next release),
check the paragraph entitled "External toolchain backend" in the 3.1.1 section.

Basically, if you want to build a toolchain with BR, but avoid de
remove and rebuild it after each "make clean",
you should build the toolchain first with Buildroot in some place (see
then use it as an external toolchain in another configuration, in
another build directory
(see http://buildroot.org/downloads/manual/manual.html#external-toolchain).

To do so (after backuping your current BR config):

1) run 'make menuconfig O=/path/to/somewhere',

2) set the same toolchain configuration as your working configuration,
and disable everything from the following menus:
- System configuration
- Package Selection for the target
- Filesystem images
- Bootloaders
- Kernel

3) run 'make O=/path/to/somewhere'.
This should build the toolchain and pretty much nothing else.

4) run 'make menuconfig' and update the toolchain configuration:
Toolchain type (External toolchain)
Toolchain (Custom toolchain)
Toolchain origin (Pre-installed toolchain)
(/path/to/somewhere/host/usr) Toolchain path



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