How do I reprogram Mac BIOS chip exactly?

Hi experts,

I have a 13” 2010 MacBook Pro.

This machine has green light on the MagSafe and will boot with chime as soon as I plug in MagSafe charger.

The screen stays black, but when I put in external monitor it will show the Apple logo and load about 1/3 and hang.

So far I disconnected the internal HDD and tried to boot of external HDD, same result, boot and hang.

I disconnected keyboard and booted with external keyboard, same.

Did the SMC reset with no response, PRAM reset same, no change.

I disconnected the battery and reconnected, still same. Disconnected machine's display, to eliminate possible short in there.

I’ve been told to: Try new BIOS, with clean ME. So I now have a EEPROM BIOS USB Programmer CH341A + SOIC8 Clip + 1.8V Adapter + SOIC8 Adapter at hand. I’ve been told by logic board repair gurus with very little patience for “noobs” that I MUST remove SPI chip U6100 and reprogram it with external programmer.

I still do not know how exactly to reprogram U6100, if removing the chip is necessary, since I do have the jumper wire and clip, and in general looking for a link to show me how to do this without frying my board. And finally what is meant with: Upload somewhere your BIOS backup. I hope this is not too much to ask??

Update (12/07/2018)

Oh, and I did run EFI ASD and it showed no errors…

Update (12/08/2018)

I had look under the logic board to see what I might find, and to check the power rails, as you suggested: So far I found amongst the regular chips:

1 Potato chip in a bed of dust, 

​​​​​​PPBUS_G3H: 12.59V

PP3V42_G3H: 3.49V

PPVRTC_G3H: 3.33V

PP5V_S5:  2.22 V on various test points, 

Then I nearly burned my finger on  L5801 which is on PP5V_S4_P18V5S5 (Booster for sensors) , which showed OL across the coil and short to ground on both sides.

Could this be the culprit? And would replacing it might make a difference? While all this sounds very techy, I am still totally a “ noob”, but one with schematics and boardview….

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pretty good for a noob, especially the identification of the potato chip ;-) Would love to see photos of your power grid on your profile.

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Hey folks, yes , I’m mighty proud to be at least able to distinguish a potato chip from the other chips!

@mayer, I already had tried the booting off an external HDD, and I think it was even with El Capitan, or perhaps Snow Leopard…I have various fresh install HDD here in my box of tricks. I like the KISS principal, along with WIT (whatever it takes).

As requested by my benefactor here, I posted my power plant , anti-climatic as it might look, on my profile. However, it works, 200w over 24 hrs makes 4.8 kw /day, enough for all my needs.

Dan, much gratitude to you for helping me avoid the confusion the BIOS flashing would have created. The Rossmann crew advises, as follows:

“Remove R5805 and test again 5V_S5. If you get correct value, then see if you get into OSX. If yes, re-solder R5805 and dig in U5805 area. If L5801 still hot”

I will have to look on the schematics and see if I can comprehend the role of R5805 and how I can get a correct value without it being there….As I said, my understanding is still mighty spotty…

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R5085 feeds U5805..it might be by experience the guys at Rossman's believe that this IC might be involved in causing the short on your S4 line. A short is usually the first thing one has to deal with when trying to troubleshoot a board.

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Mayer, when I had booted of external HDD, using external keyboard and external monitor, it resulted in the logo and the 1/3 progress bar on the external monitor, and just hung there.

Solar must be the way to go in Texas, just need to throw a lot of cash on the battery bank. Mine is lead/acid for forklifts, and was about $4500, but its good for 25 years. Now in year 13.

Back to the 820-3115-B:

As advised by my Rossmann connection, I removed R5805, which resulted in fluctuating voltage measured at P2 of the removed R5805, as well as on P1 of C5800 /L5800 respectively. At first reading it was 2.7V, a minute later it had gone up to 3.8V only to go down again a minute later to 2V and ending up at 0V. D5802 is now also at 0V. Things were heating up at first measuring, noticeable at Q3510  and at U5701  but that has now stopped...Can anyone make any sense of this?

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Shall I put R5805 back in to see if it I at least get some voltage back these C5800 and L5800?

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Lets backup here… What happens when you run the onboard diagnostics? Press and hold the D key during boot up

Reference: Mac startup key combinations

As far as reprograming the system BIOS why is that your first direction? What’s the systems history.

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Thanks for your response, Dan.

I tried pretty well all boot up combos including D, ( but not Verbose yet) with the screen remaining black. Then I went through all the tricks as I mentioned above, disconnecting peripherals etc. The history is that it is a friend’s machine which simply stopped working…black screen, chime but no complete boot up. No evidence of spill on the logic board. The bios direction came from Louis Rossmann's forum on board repair. However, I am a bit disappointed with the apparent disregard for newbies on that forum. They assume that I am in the know, but I am not there yet. I simply cannot find a decent video in English on how to do the reprogramming of the BIOS chip on a MBP. I know where it is, and it is dawning on me how incomplete booting relates to the BIOS. Did I answer your question? Do you have a better idea on how to solve this riddle? I am all ears. Cheers, J

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From what you're telling me, I'm suspecting you have a power issue not a BIOS.

You'll need to check the power rails as I'm suspecting you have an issue there.

I would also check the displays backlight logic as that could be pulling the lines down.

The fact the Apple logo is showing up and the bar is getting to the 1/3 point points to passing the first part of POST just not able to get to the second phase when the dedicated GPU and its drivers are loaded (NVIDIA GeForce 320M).

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Would your hunch of the driver load problem not show up when I ran the EFI ASD?

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Onboard diagnostics or ASD both leverage the EFI (BIOS) services to run. They only check hardware level issues they will report the driver info (just like the 'About this Mac' offers in the hardware report.

I would check the power rails as the dedicated GPU is not responding.

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Thank you, Dan

I will follow your pointers and let you know what I find. Last night I forgot that I had the machine on the MagSafe charger and the battery plugged in. When I discovered the machine later, it was too hot to touch in one spot on the logic board, which might further hep to pinpoint a possible short.

Thank you again for being accessible, knowledgable and your willingness to help …

It makes these inquiries into the currently still unknown to me, so much less daunting.

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PP5V_S5 at 2,2v , a shorted S4 line and a toasted coil are surely enough to prevent functioning. PP5V_S5 is a critical line, you'll have to get that back working and get rid of the short before anything else. Luckily you didn't get into Bios mess, would have just added confusion and probably driven you into a rabbit hole.

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Yes! You'll need to first clear the short and replace any damaged components as @arbaman stated.

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I would really love to see you try to boot from and external drive with El Capitan before you take more drastic fixes KISS (keep it simple)

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Jurgen será eternamente grato(a).
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