[OE-core] How to patch a local file in a simple elegant way?

[JH]

Hello,

Is anyway to patch a local file without committing to the git source?
I did not realize a local patch is that hard or if it is impossible.

In my OE build, I want to make a patch file for mx6ullevk.h in
meta-freescale/recipes-bsp/u-boot/u-boot-imx_2017.03.bb, to customize
mtdparts and bootargs as I could not find a simple way to do it using
bbapaend, I did not and I don't want to submit the patch to the git
source. So I got a bunch of errors:

ERROR: u-boot-imx-2017.03-r0 do_fetch: Fetcher failure: Unable to find
revision 8be98e9322040c655b9e5c9fb2c494e002e3fad9 in branch
imx_v2017.03_4.9.123_imx8mm_gafile://mx6ullevk.patch even from
upstream
ERROR: u-boot-imx-2017.03-r0 do_fetch: Fetcher failure for URL:
'git://source.codeaurora.org/external/imx/uboot-imx.git;protocol=https;branch=imx_v2017.03_4.9.123_imx8mm_gafile://mx6ullevk.patch'.
Unable to fetch URL from any source.
ERROR: u-boot-imx-2017.03-r0 do_fetch: Function failed: base_do_fetch
ERROR: Logfile of failure stored in:
/build/Installation/sa_platform_build/Source/Yocto/build/tmp-glibc/work/solar-oe-linux-gnueabi/u-boot-imx/2017.03-r0/temp/log.do_fetch.25780
ERROR: Task (/build/Installation/sa_platform_build/Source/Yocto/oe-core/../meta-freescale/recipes-bsp/u-boot/u-boot-imx_2017.03.bb:do_fetch)
failed with exit code '1'

Googling Internet, there are many suggestions to workarounds, git to
local repository, git to your own repository, or even copy all git
source to build u-boot offline. None of is elegant, I am sure there
are some nice way to do it. Could you please advise if there is a
simple elegant way to do it?

Thank you.

Kind regards,

- jh