Removing the necessary screws required to gain access into the innards of the PSP Go.

On this device, all screws are readily accessible and use a common Phillips #0 head. No hidden tabs or tri-wing screws here.

With a non-soldered battery and Phillips head screws, why doesn't Sony approve of DIY battery replacement?

We can think of only one reason: it starts with "cha," and ends with "ching." That's right, the sound of the cash register.