GrapheneOS has such low count of devices due to strict support for security features reasons.
These projects (Linux on mobile) are even more limited due to very poor support from the manufacturer for anything more than OEM and device specific build of Android, with lack of standards in mobile platforms.
Every device support is reverse engineering effort.
See https://wiki.postmarketos.org/wiki/Devices for the status of this effort.
Comments
GrapheneOS has such low count of devices due to strict support for security features reasons.
These projects (Linux on mobile) are even more limited due to very poor support from the manufacturer for anything more than OEM and device specific build of Android, with lack of standards in mobile platforms. Every device support is reverse engineering effort. See https://wiki.postmarketos.org/wiki/Devices for the status of this effort.