Guess I lucked out

I was just looking at the Japanese PSP page, and noticed that they've added a new warning to their firmware update page:

CAUTION: This update is only for customers who obtained PSP® (PlayStation®Portable) for Japan which model number is PSP-1000 or PSP-1000 K. Upon completion of preparing, we will announce update information for the other countries/areas customers via SCE Group Web Site or other channels . For these customers who obtained PSP® in the other countries/areas, please DO NOT update PSP® through this web site. There are no guarantee of proper operation of the other PSP®.

Mine still works fine, knock on wood.

And this is excerpted from Wikipedia:

Reports have shown in message boards that downloading the firmware can void your warranty or ruin your PSP. This is true because SCEA voids warranty on firmware updates that have not been authorized by SCEA since SCEA represantatives did not know anything on the 2.0 firmware when it was released, which will void your warranty. According to IGN, Sony Computer Entertaiment America will release the U.S firmware update on August 12, and American PSP users who updated their PSP's to the Japanese 2.0 firmware will be able to update to the U.S version of 2.0. Sony has announced that every single firmware update is specific for that region only.

My 1GB Memory Stick PRO Duo is scheduled to arrive via post on August 12, so I guess that's perfect timing for me.