I got psp 3004 ver 6.20 Before i ws using 6.20 TN-A (HEN) and ws havin problem wid runnin some games, help plz?

M new wid my psp its psp 3004 version 6.20. Before i ws using 6.20 TN-A (HEN) and i ws having problem wid running games like iron man, xmen legends so i changed it to 6.20 TN-B (HEN) and now even those games like tekken 5, fight night round 3 etc that where working before are nt working now. Plz help i have no idea what to n i dont want to downgrade my psp coz i heard there are risk to get brick. Moreover i dont know how to downgrade.