Nothing can be done about the fundamental insecurity of my old Pixel 3a, but it still bothers me a little bit, just having it lying around when it works fine. Recently, I was thinking about making an offline laptop without microphones and cameras, when I got the idea that just maybe, this could instead be an actual good use for the phone. However, I've never modified a phone like that, and I need to be pretty sure I don't overlook something, so I'd like to know whether anyone here has experience or advice for my situation.
Some more details:
- I'd use the phone mostly for taking notes or looking something up in a calendar in an environment where no devices containing microphones are allowed
- To make sure nobody is listening, I'd need to remove all cameras, microphones and maybe speakers
- Of course, the text I'm typing would also be sensitive, so I'd need to make sure no one gets into my phone. Because of its outdated security, I'd assume that this can only really be achieved by removing literally all wireless functionality
- I'm not yet sure about physical security. I'd probably be able to make sure no one can secretly install malware physically while I'm away without me noticing. However, idk how secure it is against someone trying to unlock it (assuming it's in a state of BFU and I have nine random words as passphrase). I also don't know whether, if they'd succeed in that, they'd be able to read the content of deleted files, although that might be mitigated by using dedicated profiles and deleting them after.
- Lastly, I wonder whether the last version of GrapheneOS or DivestOS would be a better, even though it probably doesn't change much.