Getting 3.6V from a 5V output

Hey guys, I have this switching PSU (I think) I recycled from a dead DVD player.
My goal is to use it to power an old phone and use it as mp3 player.
The PSU seems to have multiple rails, the closer one is +5V and the battery phone is 3.6V (its label is damaged that's all the info I was able to obtain from there).
What regulator/circuit do you guys suggest for this case?

If the 5 volt output is already stabilized, l’d consider using 2 normal silicon diodes (e.g. 1N400x) in series to drop the 1.4 volts.

A standard low-dropout linear 3.6V regulator seems a reasonable choice - if the phone isn't trying to
transmit it won't need huge currents (over 2A spikes if it is, though), but I'd measure the current
it takes and add a generous margin to select a part.

Alternatively a buck converter would be more efficient.

If you can get a part number off the "regulator" chip, on that PSU, you might be able to locate any "voltage programming" circuitry [usually one or more fixed resistors, but might also include a trimmer, or in rare instances a zener]. Though, for a production targeted unit, it's probably a chip designed to only produce 5V, but you never know.

If you're able to discern voltage adjusting components, and if the spec sheet for that regulator chip specifies the part can be adjusted to 3.6V, you might be able to change one or more of those components [or merely adjust the trimmer] down to the target voltage.

It's a longshot, but worth considering, no?