A potentially fatal viral infection kept Hull out of much of the 2003–04 season, although he still was able to reach his first ever quarter-final at the 2003 Welsh Open. He later repeated this result at the 2006 Malta Cup. However, his performances were largely inconsistent due to his health issues. He was forced to pull out of qualifying for the 2007 World Championship due to an irregular heartbeat thought to be linked to his past illness. After similar problems in the following season, he decided to retire from professional competition. He started working as a snooker commentator on Finnish Eurosport, and opened a snooker club in his hometown of Espoo.