AMIBIOS 1.x (or AMIBIOS 1.0, version number presumed) is the first version of AMIBIOS released in 1985 by Access Methods Inc., the predecessor of American Megatrends Inc. (AMI). Like the first instances of other BIOSes from competing companies (such as Phoenix Technologies' PhoenixBIOS and Award Software's AwardBIOS), it is fully compatible with the original IBM PC BIOS, allowing other OEMs to produce compatible clones of IBM's system without reverse-engineering its BIOS.
As of November 2024, only a limited amount of instances of AMIBIOS 1.x are known, such as the one for a 286 motherboard made by Flying Triumph Inc.
AMIBIOS 1.x was replaced with AMIBIOS 2.x in 1986.
POST screen
The POST screen of AMIBIOS 1.x is very similar to those of AMIBIOS 2.x and AMI Plus BIOS, with a prompt (usually set to the Escape key) to skip the enhanced memory test at the top and copyright text with the BIOS identification string (labelled the reference number or "Ref no.") at the bottom.
However, on some instances unlike on newer versions, there is no copyright text at the top. On these instances, only the memory test result (in kilobytes) can be found there. On other instances, a top copyright text is present, however it's in a different format (BIOS (C)AMI for (OEM/brand)) compared to the ones in the newer versions.
The detected error list and the "RUN SETUP" prompt are also different from the newer ones. Both the list and the prompt have an additional empty space before each line and on the "RUN SETUP UTILITY" line there are three starts before and after the text. On newer versions, both the empty spaces and the stars were removed.