The following are known Action Replay Codes for Robopon 2: Ring Version on Nintendo Game Boy Advance (GBA).
These codes were also known as GameShark Codes and in most cases will work on both devices.

These codes are for the U.S. version of the game.

Master Code – Must Be On
4668ae12
9a4de47c
26419fbc
a5b3d856

Have Tons of Cash
76217fbb
b03222d3

Robo 1: Infinite Health
3e95fa40
f0aa3971

Robo 1: Max Health
71ad2e23
af1335f8

Robo 1: Infinite EP
e29ed3d6
a1887db1

Robo 1: Max EP
9c5ccdc3
b3c80514

Robo 1: Max Stats
5e120445
acadcccc
5dbabbb4
31555e55

Robo 2: Infinite Health
69ea7c2f
3543512b

Robo 2: Max Health
46eafcc4
7694b22b

Robo 2: Infinite EP
1b1dc8f3
11c4e817

Robo 2: Max EP
1196d443
b9c214c1

Robo 2: Max Stats
e9d3e75e
f62c9d9e
da63f61b
90827fc4

Batteries (Code 1)
e116c61e
8089872f
c9de53d9
7c154a4d
d12dd61b
82bb92ac
875e4290
80e435ff
1f483fdd
b8ce07c1
e2f1a477
b6efbb9d
41f68a33
6c692a57
ea6bcfab
5b569087
b4c5f98d
dd321d3d

Batteries (Code 2)
42b756b3
200b0562
7098ba0d
090bcc2f
0982cd04
92f55e65
dc6233d0
17139868
b72de2d9
9fcd3aa3
a38e2ad7
6135147e
af43958b
81cb115e
0d8411b3
cec744a4