Android is built on top of the Linux kernel, which means OEMs are obligated to provide source code, upon request, for all Linux kernel binaries they distribute on the devices they sell. Some companies are quicker to release their changes than others, but after more than a month on the market, the kernel source packages for Samsung’s latest foldables – the Galaxy Z Fold 4 and Galaxy Z Flip 4 – are out. finally available.
Samsung has released kernel sources for both devices on its Open Source website. To download the zip file with sources, go to Samsung Open Source Release Center and search SM-F936 for the Galaxy Z Fold 4 and SM-F721 for Galaxy Z Flip 4.
Current versions correspond to the software version AVGA, intended for US carrier variants. Keep in mind that hardly any of the Samsung Galaxy smartphones sold in the United States can actually be unlocked by the bootloader. Unlike the global models, these devices are fully locked down. While the GPLv2 license requires vendors to release their kernel sources, the lack of an unlockable bootloader makes it very difficult to get started in the aftermarket development scene.
That said, access to kernel sources gives power users the ability to dig deeper into the code that runs the device, given the bootloader unlockability on global models. Tweaking sources often allows the modding community to come up with custom kernels that add new features not otherwise offered in the stock configuration. Kernel source builds also help developers port popular custom ROMs (e.g. LineageOS) to the device, which benefits users who are unhappy with the stock ROM or want to continue using their devices even after the end of official software support.
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 your newly created development work.