6.20 TN-D Permanent patch
Virtuous Flame has released a patch that will write to flash0 and give your PSP a permanent 6.20 TN-D state. Its risky, so try this on only PSP-1000 or PSP-2000′s pre TA-88v3′s or ones that can take a Pandora battery. There have been some reports of success and reports of bricks on PSP Go systems. Its risky and I personally don’t think its worth the risk to save 20 seconds or so.
Edit: Ok so there is a test mode, run this first. If it fail, you’ll brick so don’t flash it!
Source: Virtuous Flame blog