Bingo! The latest BIOS release for the board says it supports Sempron.
However, if the old BIOS is in the board, will the board boot so
you can install the latest BIOS ? That is the question.
So really the question is, where you are buying the board, can
they open the box and tell you if the BIOS is later than 1.2 ?
(The BIOS notes say 1.2 was the first release, and 1.3 is the
one with Sempron support.) If they have really old stock, it
might have that older BIOS in it.