Date: Wed, 21 Oct 1998 16:28:11 -0700 From: Mike Smith <mike@smith.net.au> To: John Birrell <jb@cimlogic.com.au> Cc: hackers@FreeBSD.ORG Subject: Re: BIOS extension format Message-ID: <199810212328.QAA02805@dingo.cdrom.com> In-Reply-To: Your message of "Thu, 22 Oct 1998 09:12:20 %2B1000." <199810212312.JAA00857@cimlogic.com.au>
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> > Does anyone know what format Phoenix uses for their ROM bios extensions? > I know the bios checks for an 8-bit checksum over the entire block > and it expects a magic number of 0xaa55. The user docs say that the > bios gets the size of the extension from the "extension header". From > the 3 bios extensions that I have, it's not obvious where that size > is stored or what the entry address is. 8-( > > I've tried asking (a) the board vendor (Intel); (b) the board manufacturer > (Radisys); and (c) Phoenix. Best guess is it's the format described in the PnP BIOS document, where the image starts with: offset length ---------------------------------------- 0x0 0x2 0xaa55 (signature) 0x2 0x1 length/512 0x3 0x4 initialisation vector 0x7 0x13 reserved 0x1a 0x2 offset to expansion header The expansion header generic format is: offset length ---------------------------------------- 0x0 0x4 $??? (??? is specific to option type) 0x4 0x1 structure revision 0x5 0x1 length/16 0x6 0x2 offset to next header (0 if none) 0x8 0x1 reserved (? spec says 0xffff!) 0x9 0x1 checksum 0x10 ? header-specific data There's more specific information here on PnP devices intented to participate in the boot path (disk, screen, keyboard etc.) if this is looking promising. The document you want is "Plug and Play BIOS Specification" (version 1.0A); you should be able to get it from Microsoft under http://www.microsoft.com/hwdev/respect/pnpspecs.htm in Word format (*sigh*). -- \\ Sometimes you're ahead, \\ Mike Smith \\ sometimes you're behind. \\ mike@smith.net.au \\ The race is long, and in the \\ msmith@freebsd.org \\ end it's only with yourself. \\ msmith@cdrom.com To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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