Issue with EFI Clean dump for MBA 13" 2013 i5-4250U

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1 year 2 months ago - 1 year 2 months ago #11343 by ryan
Hi all.

First of all, I'm glad to be now part of this community. Great site, congrats to the whole staff!

I recently received the machine in the subject, showing the infamous chime loop. I managed to purchase a CH341A programmer and a SPI flat cable. After some difficulties understanding the fine and obnoxious positioning of the pins (they can't be too deep inside of the programmer, nor can the whole connector lean on one or the other side...) I was able to get everything set. By the way, I work on an iMac and I installed flashrom. So it took another while to understand the syntax of the command lines but finally I was there. Programmer detected. Then I got the chip detected, though it showed some different chips I should choose among.
The problem I encounter now is the following. I downloaded here the zipped bin file (, decompressed it, launched it with the following command:

sudo flashrom -p ch341a_spi -c MX25L6406E/MX25L6408E -w 2632.bin

In return I got

Error: Image size ( 8388610 B ) doesn't match the flash chip's size ( 8388608 B ) !

I get the same error message if I use the chip MX25L6405D.
Can anyone help, please?

Thanks in advance.

P.S. I don't have any original bin file of this machine
Last edit: 1 year 2 months ago by ryan. Reason: Cleaning unwanted code and emoticon lines

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1 year 2 months ago #11344 by drgn997
the error you get is telling you the file is bigger than what the flash chip can store.
I've downloaded the same file using post information and I believe I've found your problem.
Just follow the instructions at the firmware repository:
"To use the EFI firmware that can be downloaded from the details view, simply find-and-replace "<Model-Number>" OR "SerialNumber" with your own SERIAL number."

In this repository file you will find "<Model-Number>", which is a 14-byte string, but when you replace it with your own SerialNumber which is 12-bytes, the resulting file will be 8,388,608 bytes long and FlashROM will not complain and allow you to flash the chip with it.

Good luck!
The following user(s) said Thank You: ryan

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1 year 2 months ago #11345 by ryan
Thanks a lot!
I double checked and realized the chassis carries a 2013 serial, but the logic board is actually a 2014. Downloaded the i5 dump (as i7 is missing) and the bin's dimensions are now correct. Just flashed it, all went smoothly.
I don't have backlight (I can see the images using a flashlight, so that might depend on the display or other issues on the logic board). Another issue, probably bound to the EFI version, is the delay of some seconds before it chimes, and it's taking several minutes loading high sierra from an external hd. That is, after the mandatory SMC and multiple PRAM reset.

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