Modifying libiio recipe

Hi , I have questions on how to effect some changes I want in libiio bbappend recipe in meta-adi zedboard.

I would like during petalinux-build for the build process to download a libiio of specific commit or to checkout that specific commit (can be through its SHA ID) then to build that and to include to the final Linux binaries. Another way can also be myself getting a local copy of libiio, checking out a specific commit of it, and specify the libiio bbappend recipe to use that local libiio during petalinux-build.  How to do that?

The context behind it is actually I was wondering why the libiio USB backend is not working in my recent 2 builds. Only iio_info -s command works in the host, and I haven't changed anything in the host side in terms of installed libiio in it. I pulled back some older petalinux images I have built around 3-4 weeks ago and they work in terms of USB backend. That 3-4 weeks ago are when I got the USB backend working c/o  but right now it won't.  The last builds that worked were during Sept 24 and Sept 30.  I'm thinking the recent libiio releases which are being downloaded by the meta-adi recipes might have some changes since then. As I've said, nothing changed in host side, my kernel has been localized since September (I don't know how it happened - maybe due to repeated builds - but it has the kernel source inside /components/yocto/workspace/sources/linux-xlnx and not inside build/ directory which I can modify and effect the changes without yocto patches) so I guess the only thing that could change is libiio. And so my goal for now is how to get libiio I'm using reverted to its earlier commits in the master, around September.

Inserted clarifications inside description.
[edited by: ubermensch at 3:05 AM (GMT -4) on 19 Oct 2021]