Innotab 3s vs Innotab 3s Plus?

[Evilincorp]

Hi, a little confused by Amazon. They have the 3s and 3s Plus as two different products even though they seem to have the same features. Are they the same?

3s
http://www.amazon.com/VTech-InnoTab-Wi-F...B00CMNX8WA

3s Plus
http://www.amazon.com/InnoTab-Plus-Learn...B00KS11AXM

They're even different prices with the 3s Plus being cheaper.

Will the firmware work on both, assuming they're different?

Thanks