Nice work! This reminds me of the Openmoko phone project, which I also used/liked a lot. However: Why did you choose aarch64 over a x64 CPU, e.g. a Celeron or alike that allows various clock speeds? Chrome and many x64 packages won't run on this device (Chromium does, but it won't sync with Chrome accounts any longer). Take a look at GPD's microPCs: They work perfectly with most mainstream Linux applications. x64 is not power efficient for low-complexity software, but beats aarch64 when executing inefficient code, i.e., complex tasks. Since most software won't be re-written specifically for this device, it might be less of a hassle to adapt the device to the plethora of inefficient, yet existing software. I am aware that sleep/standby might harder to implement, but a hybrid system with an aarch64 'phone' peripheral component and a x64 'main PC' might have solved it. This has existed before (e.g., Nokia 9210 Communicator) where the main computer and the 'phone' were two independent devices that tightly interacted. Maybe a later model adds x64 cores.