Baby Universe (SCPS-18006): Audio CD swap feature does not function

[digital-pet]

tonyhax version: v1.4.5
Installation method: Dexdrive
Entry point game: THPS2 US
Console model: SCPH-9001
Integrity check: Passed
BIOS version: v4.1 12/16/97 A
Target game: Baby Universe (SCPS-18006) (burned backup on azo blue CDR)

Bug explanation:
When swapping in an audio CD to use Baby Universe's soundscope mode, it fails to properly read any inserted audio CD, causing the game to hang until the Baby Universe game disc is re-inserted. The audio CDs tested are Incubus - S.C.I.E.N.C.E. (EK67927), Death - The Sound Of Perseverance Disc 1 (RR7154) and Bangarang & The Wonder Years Split EP (FFR001)

[alex-free]

This is really weird.

Mod chip console booting baby universe = can play a burned audio CD.

Japanese console using Tonyhax International = can play a burned audio CD

USA/PAL console using either original Tonyhax or Tonyhax International = gets stuck on "checking CD" forever. Cd will constantly spin up for a few seconds and then stop.

Pretty sure the unlock is conflicting with this function somehow because the Japanese console using International has no issues since it is not unlocked. Mod chip was also fine.