I talk about 6.72 but the slim is on 5.55. Any interest in keeping this firmware in the hope of a new exploit. Why 5.55 isn't compatible with 6.72 exploit?
5.55 is much better, more stable, but in the end its up to you. Almost the same as 5.05.
Anyway, you can find the 5.55 exploit on chendochap's github
Maybe look at joonie86 twitter, if you can't find it.