[coreboot] BIOS Savior (RD1-PMC4/8X) unavailable? Build my own?
lineage2005 at gmail.com
Thu Nov 15 02:31:21 CET 2012
Thank you Dave and Andrew for your responses.
I started digging around and have gotten parts for such a creation and
ran across this  thread which was of great help in confirming the
design of the hack. Doesn't read like it until they get into the dual
flash discussion but did have relevant information about the chips I'm
Finding the PLCC plug turned out to be an adventure in frustration and
I hope to have it in hand before the Thanksgiving holiday closes to
run some tests while on a break.
I do hope to get some pictures (and maybe a parts list) during the
build so I can share them on the wiki.
Thanks again and I will hopefully have a working switchable BIOS
solution for my environment shortly. Then on to the gritty part of
getting my northbridge initialization coding skills up to speed. Still
need to get a working QEMU build done but the parts hunting and fact
verifying of this hardware hack have been time consuming. :D
On Fri, Nov 9, 2012 at 11:51 AM, Dave Frodin <dave.frodin at se-eng.com> wrote:
> My comments are inline below.
> ----- Original Message -----
>> From: "Milo Hoffmann" <lineage2005 at gmail.com>
>> To: coreboot at coreboot.org
>> Sent: Thursday, November 8, 2012 11:29:41 PM
>> Subject: [coreboot] BIOS Savior (RD1-PMC4/8X) unavailable? Build my own?
>> Hello list,
>> I might be missing something here, but I've spent all day trying to
>> find a vendor (anywhere) who actually carries the BIOS Savior model
>> I've determined I need. I did find on the ioss website that they have
>> stopped manufacturing (I believe that's what they were trying to say)
>> the models I need. 
>> I have a PLCC32 socket (holding an SST 49LF004B) and the ioss
>> reference page  indicates an RD1-PMC4 or RD1-8X (not 8X2).
>> So... I started down the line of thought that I should be able to
>> build my own, or come close enough to it with a switchable solution,
>> for testing.
>> Digging around, I found the wiki page indicating that it was possible
>> to build your own . There was no PLCC example, so I searched a bit
>> more and found this  thread and this  reference. The thread
>> included a quick and dirty explanation of setup (provided that you
>> have identical chips) along with other useful hints. The reference
>> was less helpful unless I can get a 8Mb (1MB) flash chip that is
>> otherwise identical to the SST49LF004B.
>> But, the thread also said I would need a "32pin PLCC-Plugin-Adapter"
>> for which I have found a few part numbers but no US distributor
>> (haven't looked international yet).
>> I have the datasheet for the SST49LF004B (and two known working
>> but don't know the rest of the equation.
>> The datasheet does not include the /CE pin from the quick and dirty
>> explanation. I interpret it to mean the WE# (Write Enable) pin but am
>> seeking confirmation from more informed folks.
>> Can anyone on the list confirm I could hook up two identical
>> SST49LF004B, using the WE# pin, to a three wire switch and have a
>> functioning switchable BIOS?
> If you are switching between two flash devices you would want to be
> switching between the two CE# signals. Switching between the two WE#
> signals would only disable writing to one device, and reads would be
> sourced by both devices. You would need a separate pullup on each
> devices CE# signal so that when that devices CE# isn't being driven
> by the mother-boards CE# output that device would be disabled.
> The devices don't necessarily need to be the same exact device, unless
> there is some other constraint (e.g. size, flash support,etc).
> You could have a SST49LF004B in one socket and a SST49LF002 or SST49LF008
> in the other socket. They wouldn't necessarily even need to be the same
> brand. They would both need to be FWH flash devices though. Most chipsets
> have a strap that determines whether the ROM R/W cycles will go out on
> the LPC bus as FWH or LPC-memory cycles.
>> Is the more elegant solution to also find a PLCC Plug (like say,
>> Winslow Adaptics W9302), two PLCC sockets and some board with which
>> stick them all together?
>> I would really like to return the 'spare' SST49LF004B back to it's
>> board once I have a working coreboot firmware load. (I'm sure I'll be
>> asking questions about that soon too. Still trying to get a QEMU
>> coreboot working... hehehee...)
>> Thanks for any response.
>>  http://www.ioss.com.tw/eg/orderform0703.html
>>  http://www.coreboot.org/Developer_Manual/Tools/Dual_Flash
>> [EPIA flash questions]
>> [Homemade BIOS switch for EPIA boards (and others with 2MBit chips)]
>> coreboot mailing list: coreboot at coreboot.org
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