> not sure what to make of "genuine" and "OEM" claims for a battery for a 16–year-old device
They're lies, but the batteries work. There were Chinese lines manufacturing knockoff BL-5Js, and there may still be one or two, or just a bunch of crates filled with old ones. Source: still use an N900, but just for podcasts.
> 10-year-old if you count compatible Lumias
Worse, those Lumia BL-5Js aren't actually compatible. The slots cut into the battery aren't wide enough to fit into the N900. Unless you're willing to cut apart the battery itself, they're useless.
They're lies, but the batteries work. There were Chinese lines manufacturing knockoff BL-5Js, and there may still be one or two, or just a bunch of crates filled with old ones. Source: still use an N900, but just for podcasts.
> 10-year-old if you count compatible Lumias
Worse, those Lumia BL-5Js aren't actually compatible. The slots cut into the battery aren't wide enough to fit into the N900. Unless you're willing to cut apart the battery itself, they're useless.