All F1 Savannahs are considered "A" generation cats, even if their domestic parent is a Savannah. This is the very first step toward achieving an SBT Savannah Cat. 

The International Cat Association (TICA) considers the SBT Savannah eligible for competition
in the championship show ring and a fully accepted domestic breed of cat.

F1 Savannahs have no less than 50% Serval genetics, and typically no more than 75%.
There are, however, a very small number of breeders choosing to breed backward to the Serval, rather than forward with a Savannah.  This raises the percentage of Serval, but moves the resulting offspring no closer to SBT status.  Additionally, it creates fertility issues in the later generation males.

NOTE: High percentage Savannahs may not be shown or exhibited at TICA shows, despite their later generational qualifications (F3 and later), without permission first from the show manager, full disclosure of their high percentage ancestry to both show manager and to each TICA judge, and if the show manager accepts the high percentage cat into the show hall, the handling is fully at each judge's discretion.