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Old 03-25-2015, 12:08 PM   #126
Per Hansson
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Default Re: Dell Precision 470 Workstation

Hi, small update here, I bought 8GB of Micron MT36HTF51272PY-40EE1 memory on eBay, the PC booted with one stick but the other was bad (physically damaged, cracked memory chip and destroyed resistors & capacitors) seller refunded me though so all was fine

Not feeling let down I looked more on eBay and found 16GB of the PC-6400 version of the same memory: MT36HTF51272PY-80EE1
Bought that thinking it's a good idea since it will be more useful in the future aswell vs the other memory which was only rated for PC-3200

But with that memory the Dell just gave the "memory error" beeps at startup
Looking into it I found a website selling a software for modifying the SPD data:
Thaiphoon Burner Super Blaster Personal Edition (Might be the most ridiculous name for anything, ever)

And luckily the ST M34E02 EEPROM containing the SPD data was not write protected, even though it does support it and should have been according to the datasheet of the memory!

So I gave things a go, the new memory only had SPD speeds programmed for 400Mhz & 266Mhz, so I figured that must be it, because the old working PC-3200 memory only had the speed 200Mhz programmed...
But no matter how I tried adding the new 200Mhz speed the system would not boot with the memory, so I contacted their support, and they poked me in the right direction:
The PC-3200 memory had the ECC bit (byte 11) set to "02" and the PC-6400 memory had it set to "06"
http://www.simmtester.com/page/news/...ws.asp?num=139
Changing that one setting and letting the program calculate the new CRC value made the computer able to boot

Now you might wonder how I managed to write the SPD data if the system could not boot with the memory in the first place?
Well, I did the crazy thing: I booted the system with the working PC-3200 stick, and with Windows up and running plugged in the other sticks one by one and flashed their SPD EEPROM's
I should mention though that if I tried doing the same thing while having booted the PC using 1GB or 512MB sticks then it would hardlock though, so your milage may vary...
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Last edited by Per Hansson; 03-25-2015 at 12:13 PM..
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