J416's HBL port for 6.30/6.31 has been released.
The game exploited is "Minna no golf portable", the Japanese version of Everybody's Golf/Hot Shots Golf (EU/US versions respectively).
J416's blog: J416 blog
The exploit page : J416 blog
(both the above are in Japanese)
Wololo also made a post about it here: HBL Released for 6.30/6.31 · Wololo.net and mirrored the exploit here: http://wololo.net/download.php?f=hbl631-j416.zip
Wololo also mentioned that the US version of the game is exploitable, as is the Japanese sequel. I'm gonna guess that we will see a US port soon. And zecoxao from the advanacedPSP.tk forums has mentioned that he has been working on exploiting the EU version independently, and should also be able to make HBL work for it.