Basically, buy a Pixel 6 or later (I suggest Pixel 7 or later, since Pixel 6 will be minimal support soon) that you are sure has an unlockable bootloader. The majority you'll see don't have an unlockable bootloader.

Which mostly means either buy direct from Google, or buy one on eBay that already has GrapheneOS/CalyxOS/LineageOS on it or for which the seller expressly says it has an unlockable bootloader.

(IME, don't bother trying to ask a seller to check bootloader, if they haven't already said. Almost no one is going to go through the process to check, the answer is probably no anyway, they might misunderstand your question and answer that it's "unlocked", and they may be tired of people asking.)

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microtonal 2 hours ago | parent | next [-]

I'd say buy Pixel 8 or later, Pixel 8 is the first version with support for MTE, which is a significant security improvement.

	▲	realjame 2 hours ago \| parent [-]
		Pixel 8 is also the first generation of Pixels to be officially supported, both security and OS updates, for 7 years (until 2030)

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garciansmith 2 hours ago | parent | prev [-]

If you have time and the ebay listing is unclear, I would definitely ask. That way if they say you can unlock the boatloader and in reality you can't, you can return it to them as an item "not as described" at no cost.

	▲	neilv 42 minutes ago \| parent [-]
		I tried asking, years ago, with the rationale of I'm not wasting people's time, since they could get more money if they knew about bootloader unlocking. Then I decided everyone who knows about bootloader unlocking would've already checked and mentioned if it was unlockable (but not if it wasn't, since why confuse normal buyers with a fringe thing), and I've never gotten a positive response trying to tell any seller about it, so I think I'm just wasting everyone's time. Your mileage may vary.