The two firmwares have the same region layout with similar-sized firmware components and importantly they share same PCB P/Ns meaning a cross-flash is possible, albeit not guaranteed. The safest way would be to try a hybrid firmware made up of the 2270's boot.bin and the 2596's fw_all.bin & resources_7F05.bin and retaining the US HWID 2270. That way if the flash fails it is more likely to revert back to US, however it it succeeds then a full flash to APEC is almost certainly safe. Do you know how to make the hybrid fw using [Only registered and activated users can see links. ] or do you need help with that?