MacBook Air Core i5 1.4 13 (Early 2014) problems

Still no go.
Cleaned the ME region, checked with MD5 between each operation, read it back 2 times from the MB everything checks out, but the damn thing still doesn't do anything besides spinning up and down the fan.

Reverendalc, G.Beard, can you guys loook at it if it's ok? Please? Thank you.

Have you successfully used your equipment for this purpose in other scenarios?

If not:

How long are your wires

Umm, might I ask what lead you to flash the EFI in the first place...

What where the symptoms initially?
Are you a board repair tech?
Have you tested the board power rails with DMM or a O'scope or inspected with Microscope?

reverendalc wrote: Have you successfully used your equipment for this purpose in other scenarios?

If not:

How long are your wires

I did, once. My wires are 7.5 cm or about 3 inches long, standard female-female wires. I'm not doing this on a regular basis, I helped out couple of friends who bought them from sites similar to craigslist (against my advice), and got locked computers. Te problem with the current one, is that it turned on asking for 4 digit pass, since I rewrote the efi, not once came alive, that's why I try so hard to make it work, can't afford to drop 300$ for replacement MB.

G.Beard wrote: Umm, might I ask what lead you to flash the EFI in the first place...

What where the symptoms initially?
Are you a board repair tech?
Have you tested the board power rails with DMM or a O'scope or inspected with Microscope?

The reason was the efi password (4 digit). I am a repair tech, but for regular PC's and servers. I didn't check the power rails, since the MBA worked as expected before the flashing, and that's the only thing that changed, the firmware, since then, no chime, no image, just the fan spins up and 10 seconds later down, in a cycle until runs out of battery power.

i think it's safe to say nearly everybody on here is here for the purpose of removing EFI locks on mac computers (-;

i sincerely doubt it's a hardware issue, unless that hardware issue was caused during attempted flashing.

i accidentally destroyed an 1502 once when studying for notes, it's no fun.

try disconnecting the battery, holding the power button for 30 seconds, then connecting the magsafe while still holding the power button.
if it just does the fan spinny thing, power it down and attempt SMC reset.

i have 820-3437 board view and schematic if you like

reverendalc wrote: i
i have 820-3437 board view and schematic if you like

That would be helpful, thanks. I might check out the power rails, and see what's what. I haven't used my reflow station in months, so this might be the opportunity to crawl back in fixing hardware

Plug mouse to USB. Does it light up?

G.Beard wrote:

File Attachment:

File Name: 820-3437.zip
File Size:8,388 KB

Plug mouse to USB. Does it light up?

Yes, it does.
The board file is not for my MB.
www.elvikom.pl/schematic-apple-macbook-air-a1466-j43-mlb-820-3437-051-9800-t31740.html
This is the one, but I can't download that, it's a "points" based forum.

If you have 820-3437 MacBook Air Haswell logic board this is the one for your board... I use it every day. Open the board view with this application:

openboardview.org/

I just removed a BIOS chip from a board to see what would happens and what happens is exactly what you describe. Your issue is either bad flash or something got fucked up around SPI circuitry. Open file and search U6100. Forget the -A or -B bit it makes fuck all difference on these Air boards.
Once you open the BoardView file you will see that it is indeed the file for 3437. I use it every day and it earns me £££££ look again.

I agree with the beard.

My money is on bad flash somehow, because you have to be doing something rather silly to physically damage your mac while flashing the chip in place.

The one machine I destroyed while tinkering with wouldn't even respond to the power button.

G.Beard wrote: If you have 820-3437 MacBook Air Haswell logic board this is the one for your board... I use it every day. Open the board view with this application:

openboardview.org/

I just removed a BIOS chip from a board to see what would happens and what happens is exactly what you describe. Your issue is either bad flash or something got fucked up around SPI circuitry. Open file and search U6100. Forget the -A or -B bit it makes fuck all difference on these Air boards.
Once you open the BoardView file you will see that it is indeed the file for 3437. I use it every day and it earns me £££££ look again.

I used the openboardviewer for the first time, this morning I realized that there is a "flip board" menu. That was what confused me.

P.S. Where can I buy in Europe MX25L6405? TME and Farnell don't have them

It actually does not have to be the same EEPROM device but an equiv chip same pinout. But if you are going to buy a device then just buy one already flashed.

www.ebay.co.uk/itm/EFI-BIOS-firmware-chip-for-Apple-MacBook-Air-A1466-820-3437-B-/112198912597?hash=item1a1f938a55:g:C-8AAOSwYIxX5RYw


I bought one about a week ago because I cocked up and could not figure out why. I have since figured out that I needed to manually set status register value but this does not apply to your situation. I just wanted the machine to work so I could get paid. I am sure you want your machine to work too..... I say get the job done by the simplest means now and figure out your problems later when it is non critical.


Oh.. Do you have a rework station?

Yes order eBay.

I boffed an mx25l6473e once. Had to order a stupid preprogrammed replacement off eBay for $40 to get it anytime soon. I also ordered 20x mx25l6406e and mx25l6437e from china so I wouldn't find myself in that bind again. It took about two weeks to get them but I paid approx $.50 each.

I now flash them and sell them on eBay from time to time.

The beard is correct, the chip doesn't have to be the exact same part, it just has to mate with the board correctly and have the same pin function and probably rom size.

Gr-Oborona did some fun experimentation replacing soic chips with wson packages via wires and the Mac booted just fine with the proper firmware.

At any rate, if you have access to another working mac, I would suggest hooking up your programmer to it and:

Read chip 3 times, verify md5sums between the 3 reads
Then verify the read against the chips contents. This will confirm your read operation. do not perform your transactions at maximum SPI speed.

If all of that goes well, go back to your dead mac

Perform erase function
Write the dump I supplied earlier
Cross fingers lol

If you ordered an EFI destroyer, it is capable of setting write status on the chip if you're having trouble writing.

@reverendalc Here is the read from that eBay chip, I think you said you wanted to take a look the other day.

Thanks! I'm interested to find the differences (if any) between my read and the eBay dump. Particularly, to see what the ME region looks like.

These eBay dumps are allegedly (and with no evidence to the contrary) ready to go in any appropriate mac.

One long rainy weekend I want to run thru the repo and get them all game-ready too without modification (aside from serial)

OK, last word on this....
Not sure what difference it makes to the ME but the chip was powered on the board.

Sorry Kawa for the off topic.

It's not quite off topic, with each reply I learn more. Got yesterday evening a similar chip (64Mbit, same pinout), and going to replace the one from the MB to see if it works. I'll get you posted on the results, especially if successful, might help somebody else to.
Thanks guys.

great. have a look at this thread. interesting stuff

ghostlyhaks.com/forum/macbook-pro-retina-2015-2016/553-soldering-pads-on-a1502-emc2835#4156

Hi guys,
Turns out that I was expecting a SOIC8 chip instead found WSON8, so I need to buy some. My question is:
http://ro.farnell.com/spansion/s25fl064p0xnfi001/memory-flash-64mbit-3v-spi-8wson/dp/2340540
Would this one work as a replacement for MX25L56406EZNI ?
Thanks.