That work was not available when GrapheneOS was developed

What do you mean ? This has nothing to do with GrapheneOS in the first place (which by the way has been created in 2014. The article i linked refers to 2021).

I still consider it a black box.

Reverse engineering is a thing. It always has been. If every piece of closed source was a blackbox how can you explain exploitation ? How can bad actors exploit Windows, MacOS, CPU firmware and so on ? Your argument here is not practical. Also, why should Google put a backdoor inside a chip ? They already get every information they what directly from the people agreeing to use their software. So, why bother ? Moreover, every phone on the market has closed source firmware.

The Titan security chip is not a black box. The Titan M1 gas been scrutinazed by blackhat: https://dl.acm.org/doi/fullHtml/10.1145/3503921.3503922

Just because something is not open source does not mean you can't verify it (no, i'm not shilling closed slurce; no i don't think closed > open; no i don't think closed source is more secure)

Braxman's content is pure scam

Thank you for sharing!

I personally blocked him and it was one of the best decision of my digital life. He's basically wasting his life spreading misinformation about GrapheneOS. He's simply too much to handled for my mind. Without seeing him, i feel this place is much more relaxing and useful to see it.

GrapheneOS!

Hi! I know this option doesn't respect the second point of your list. That beijg said, if i was you i would buy a Google Pixel 7 or 8 and then i would put GrapheneOS on it!