Linux already on HP Prime G2!

[Jean-Baptiste Boric]

(07-18-2019 01:53 AM)Claudio L. Wrote:  Are you sure you can't replace the firmware? I don't know the specifics of this particular chip but in general even when enforcing secure boot only the lowest level bootloader needs to be signed (usually called BL1 or similar).

As I said, HP's firmware enforces a chain of trust, but the hardware does not enforce a root of trust. We can boot whatever we want, whether it's from the SoC's recovery or the NAND. However, once the calculator runs HP's official firmware it's a one-way trip until reset. The chain of trust extends to HP's official recovery, so you can't upload an unofficial firmware through it.

So yes, the firmware can be replaced, but unlike G1 we can't hitch a ride on HP's official firmware. Once HP's code runs, it's effectively game over until reset.