[Dreamcast] Serial generator notes

[Matt-Swift]

The shell command says that domain is for V1/2, and subdomain is for region (J/U/E), however I did some quick testing generating serials for each version to see what would be accepted by the generator and got the following:

JPv1: Anything gets accepted for this version it seems, would suspect domain 0 though
JPv2: Domain 0, Subdomain 1
USv1: Domain 1, Subdomain 0 (it will accept a serial from subdomain 1, however when trying to import into v2, it will reject it)
USv2: Domain 1, Subdomain 1
EUv1: Domain 2, Subdomain 2
EUv2: Domain 2, Subdomain 1

No obvious pattern here from what I can tell other than domain being for region.

[fuzziqersoftware]

Thanks for testing these - I've updated the instructions.

[Matt-Swift]

Some extra notes:

It's less complicated than I thought:

V1 accepts all serials generated in the correct domain, regardless of subdomain. (JP = 0, US = 1, EU = 2, JP actually works for any serial, even a completely made up one)
V2 only accepts the correct domain with subdomain 1. (JP = 0/1, US = 1/1, EU = 2/1)

However, when you are asked to enter your V1 serial in V2, only the correct domain with subdomain 0 is accepted. (JP = 0/0, US = 1/0, EU = 2/0)

As such, I have made #152 to update this... again!! Dunno if you'd want to note this somewhere in the repo.