- RISCV processor
- Standard Logic board
- Standard Screen
- Standard Battery
- Standard Wifi & Bluetooth modem
- Probably ditch cellular and use something like LoRa
- Standard OS (Linux)
- Standard package manager
Edit: Imagine a phone that you can just swap and mix components from different manufacturers. You could buy the components yourself and assemble, like a standard PC. If one manufacturer tries to lock you in, or you don't like their component you simply replace it.
I'll be generous and add in "standard camera" for you.
But of course camera tech is moving fast. So either the standard camera gets left behind, or the "standard camera" is continually updated.
Rinse and repeat for sll your "standards". The modem needs updating (new mobile specs coming out from time to time.) Battery tech goes very fast. Every time I eat there's a cpu update. Screens change. Form factors change.
Armies of people at Samsung, Apple et al are managing this all the time. Naturally your Open Source phone would need to keep up.
So instead of listing all the common modules, perhaps it's more useful to explain what sort of budget this effort eould need (sustainably) then list the ways the project will generate income to meet that budget.
Without this your list falls into the "what we need are flying cars" box, which is nice, but not exactly constructive. [Astute readers will also note that we really don't want flying cars...]
I think if there's an open standard that different organizations can contribute to things will move faster and will be cheaper than having single organization trying to build a new Linux phone from scratch, it is also more reselient with little centralization. Different groups can specialize on different components where they have expertise.
I chose RISCV because it's a open standard, we could build around that ecosystem.
The standard can be updated, having different generations/versions when it's absolutely necessary. But it shouldn't move too fast especially if the interfaces are clearly defined. Phones from 10 years ago are powerful enough it's just that brands create new devices to force people to upgrade.