Android is built on top of the Linux kernel, which means the OEMs are obliged to provide the source code, upon request, of any Linux kernel binaries they distribute on devices they sell. Some companies are faster to release their changes than others, but after more than a month on the market, kernel source packages for the Samsung’s latest foldables — the Galaxy Z Fold 4 and the Galaxy Z Flip 4 — are finally available.
Samsung has released kernel sources for both of these devices on its Open Source website. To download the zip file with the sources, head on over to Samsung Open Source Release Center, and search for SM-F936 for the Galaxy Z Fold 4 and SM-F721 for the Galaxy Z Flip 4.
The current releases correspond to the software version AVGA, intended for the US carrier variants. Keep in mind that practically none of the Samsung Galaxy smartphones sold in the US can actually be bootloader unlocked. Unlike the global models, these devices come entirely locked down. While the GPLv2 license requires that vendors release their kernel sources, the lack of an unlockable bootloader makes it real hard to kickstart the aftermarket development scene.
That said, access to the kernel sources gives power users a chance to deep-dive into the code that runs the device, given bootloader unlockability on the global models. Tweaking the sources often allows the modding community to come up with custom kernels that add new capabilities that are otherwise not offered in the stock configuration. Kernel source releases also help developers to port popular custom ROMs (e.g. LineageOS) for the device which, in turn, benefit users who aren’t satisfied with the stock ROM or who want to keep using their devices even after the official software support ends.
If you’re a developer looking to start building for the device duo, head over to Samsung’s Open Source Release Center to get started. Then, be sure to visit our forums to share all of your newly created development work.