How to apply patches to a package in Buildroot?

To expand on @pradeepchhentri's answer. Quilt will look for a file located in the same folder as the *.mk file. To construct the appropriate file:

1. diff your source package from the original into a file called

   packagename-number-description.patch

   where

   packagename - has to be identical to the package name

   number - is the order in which the patches should be applied if you have more than one patch to apply (otherwise it will be applied alphabetically)

   description - can be any free text

2. Place this file into the package at the same level as the [packagename].mk file and the package/Config.in file.

Don't forget to blow away your build files or do a [package]-rebuild if you do this. You should see a "Patching..." message if this is done correctly.

some details about patch files in the buildroot project:

1. you have to

   diff -u "old_file" "new_file" > file.patch
   

while standing exactly above extracted location of your package tar.gz defined in

PACKAGE_NAME_SOURCE

it means, your path to the file must include extracted package folder name.

2. in case you wonder if the "old_file" path would be different from the original one - don't worry, the important one is the "new_file" path and name - it should match your package extracted one.

3. naming convention for the patches already used/defined in buildroot (all parts are separated with '-' sign):

   • 4 digits patch priority (starting from 0001)
   • target filename
   • reason for patching
   • .patch extention

example:

0001-configure.ac-convert-AC_TRY_COMPILE-AC_COMPILE_IFELS.patch

4. deposit patch file inside buildroot/package/"your package name"/ folder.

there is no need for configuration files to modify, all patches will be tried for application automatically.

5. in case of the failure, the reject-patch file (named similar to the file you are trying to patch but with .rej extention) will be deposited inside package extracted folder.

Use *_OVERRIDE_SRCDIR and track everything in submodules

Instead of using patches, I highly recommend that you to this instead:

myproject/
  .git/
  submodules/buildroot/
  submodules/source_of_my_package/

and just track the source of your in a submodule that points to your fork of the project with your patches on top.

This will make everything much saner and easy to keep track of.

More info at: How to modify the source of Buildroot packages for package development?

BR2_GLOBAL_PATCH_DIR out-of-tree patches

Directory structure:

• .git/
• buildroot/ Buildroot submodule as mentioned at: https://stackoverflow.com/a/23635403/895245
• global_patch_dir/packagename/0001-my-test.patch

Add to config:

BR2_GLOBAL_PATCH_DIR=../global_patch_dir

Then build with:

cd buildroot
make

The patch should be applied to output/build/packagename-1.0.0/ before build.