Peter Stuge wrote: > On Fri, Sep 07, 2007 at 06:46:17PM +0100, Chris Lingard wrote: >> Gigabyte have told me that the BIOS chip is made by SST, and the >> model name is SST25LF040A BIOS ROM which is PLCC32 type. > > Nonsense, I'm afraid. > > SST25LF040A is only available in 8-contact packages. (SOIC and WSON) > > Whoever you had contact with at Gigabyte didn't know about the > different revisions of the board and their differences. > > >> I am now very confused because I have PLCC32 sockets and these are >> nothing like the BIOS chip which has 8 connections. >> >> (I have two PLCC32 sockets and four unused flash chips to give away, >> if they are no use to this version of the motherboard). > > Correct, since you don't have PLCC chips you have the revision with > SOIC chips. > > >> I will probably try to source some of these chips, just in case the >> rest of the problems can be solved. > > The hardware part is solved, but there's no support for flashing > in flashrom yet, you would have to reboot into another OS (DOS or > Windows) and use the Gigabyte-supplied flashing utility. > > > For the hardware mod you would need: > > 1x SST25LF040A or MX25L4005A > 2x 100k resistors (0.125W ones are good size-wise) > 1x SPDT (single pole dual throw) switch (break-before-make or > make-before-break doesn't matter much - neither will reliably allow > the switch to be flipped while the flash chip is being accessed.) > > See http://stuge.se/m57sli_soic_detail_labels.jpg for contact names. > > 1. Lift the U5-CS# pin from the board. > 2. Solder 1x 100k resistor between U5-VCC and the lifted U5-CS# pin. > 3. Solder the center contact on the switch to the U5-CS# pad on the > mainboard. > 4. Solder one outer contact on the switch to the U5-CS# pin, where > one end of the resistor in step 2 is also soldered. > 5. Solder the new flash chip to the U9 pads. Note pin 1! There should > be a marking on the flash chip near one corner pin, that's pin 1, > U9-CS#. > 6. Lift U9-CS# from the board. (Or just don't solder it in step 5.) > 7. Solder 1x 100k resistor between U9-VCC and the lifted U9-CS# pin. > 8. Solder the second outer contact on the switch to the U9-CS# pin, > where one end of the resistor in step 7 is also soldered. > > Done! Now the switch controls which of U5 and U9 is actually > selected when the super io wants to access the flash chip. > > > You could get a biased (spring-loaded) switch in order to help > avoiding accidentally leaving the system running with the factory > BIOS chip selected when you're doing LB work - so that the next > flashing operation does not overwrite the wrong chip. You would need > to hold the switch while booting the factory BIOS, but that may be > worthwhile if you can't easily redo the soldering work if both flash > chips contain junk. > > > //Peter
Thank you, that is brilliant. OK, two PLCC32 sockets and four unused flash chips free to good home :-) Apply by email, (or 2 sets of one socket and two chips). Will start sourcing SST25LF040A on Monday, then rebook the workshop. My second newbie dumb question. If I make copies of the Factory BIOS on a floppy, I can overwrite one of them with LinuxBios. I then use the BIOS, and when it asks for confirmation, I switch over to the new chip, and hope. (The Gigabyte BIOS can overwrite itself, press <end> key during post to enter Q-flash) Chris Lingard -- linuxbios mailing list [email protected] http://www.linuxbios.org/mailman/listinfo/linuxbios
