Click on this link:
Welcome to Yaesu.com
Then click on the Files tab.
The firmware update is the 6th listing under "Amateur Radio \ Software".
Oh, Yaesu likes to hide discontinued products on their website. From the main Yaesu.com webpage, hover over the Product menu item until the drop down appears, then click on VHF/UHF Handhelds. In the small horizontal bar, you'll see "Archived VHF/UHF Handhelds". The next screen will allow you to find old handhelds. Heck, even the FT-33R is listed, a somewhat obscure 220 MHz radio that was discontinued in the 1990s.