I'd Love some advice a1502 EMC 2678 Late 2013 13"

Hello all,

Let me start by saying thanks for taking the time to read this.

I have corrupted my EFI by performing an SMC reset while booting from a USB installer that had gotten stuck.

Now my mac only plays the startup chime on a black screen over and over with almost no lag between chimes. The ONLY keyboard inputs it responds to are SMC Resets and force power offs. ( I have tried PRAM/NVRAM, Single User, Safe Boot, Option Boot, Netboot, Diagnostic Boot, and all from both the internal keyboard and an external keyboard) So yeah, the EFI is screwed.

So from what I have learned so far from this site and others, this is my plan to flash the entire BIOS/EFI rather than just removing a password.

I have ordered a CH341a and an SOIC8 Clip

I have downloaded a clean dump that matches my model exactly (i5 2.4, 8GB Late 2013 13"retina EMC 2678)

I plan to replace the clean dump serial number with my own

CONCERNS / QUESTIONS I have

1. Does the clean dump already contain a clean ME Region or do I need to replace that from the external repo linked on this site?

2. Will not being able to change the UUID cause me issues with Applciation licensing and iMessage etc? BoneCrusher's article on UUID cleaning specifically says that his method will not work on Macbook pro 11,1 (I don't know enough about EFI to even imagine why it shouldn't)

3. I was hoping not to buy a raspberry pi, but the EEPROM flashing software I found for the CH341a is old and doesn't specifically list my chip (MX25L6406E) as compatible. Flashrom seems not to run on Windows natively....

4. Do I actually need a device like EZ Flash, or is that really just to save me the hassel of pulling the Logic board and using the SOIC8 Clip? I don't mind pulling the board if it saves me $30, it only takes a few minutes.

5. Can you guys think of anything I'm missing given that I am flashing the entire BIOS file?

A Million thanks,
Will

Well, after thinking about it more, I realized that it will be much more difficult to connect the logic board to the battery and magsafe if its pulled, not mention making sure the CPU doesn't overheat since the fan will be disconnected

SO - I have come to my senses and ordered an SPI clip and some single pin cables.

I already have the dirt cheap CH341a USB tool arriving tomorrow and my chip is listed as supported by some sources and not by others. Couldn't hurt to at least try to get a few dumps from the chip? I've got a line on a cheap used first gen Pi model B if I have to.

I'll keep this thread updated with progress if for no other reason than potentially helping others in the future

As promised, I am updating this thread:

Here's the current status:

I’m attaching my bin file with the serial number and board ID masked if anyone here is able to look at it or repair it for me, I would certainly buy you a beer.

I am now able to reset PRAM and option boot to a boot selection screen, but any images I attempt to boot from (netboot installers, netboot restores, recovery partitions, clean OS installed drives) all show a prohibitory symbol.

Verbose booting reveals this message: macOS is not supported on this platform reason: mac-d52d5b74c092159a

Internet recovery is the only option that doesn’t show a prohibitory symbol, it shows the standard spinning globe, but never actually loads to an installer.


And here's the things I found along the way:

The CH341a EEPROM Flasher was of no help, it could not read or write the chip.

Surprise: All along I thought I had a MX25L6406E chip and in the end it turned out to be an “N25Q064..3E” according to Flashrom.

I was eventually able to read/write using a Raspberry Pi gen 1 Model B, running Raspian Pixel and Flashrom

Tips that may help others:

1. I had to use the RebelSimCard SPI Clip with the switch all the way to the right if viewed with the wires pointed downward.
2. After plugging and unplugging the SPI Clip so many times trying to get a good connection, the rows of pins on the SPI header on my logic board had spread apart ever so slightly. Eventually I had to “tighten” the header by ever so gently guiding the two rows back toward each other with my finger nails on the outside edges of the pins. This resulted in the SPI clip making a nice solid connection and a good read.

I had to follow this set of steps regarding power to get it to read and write:
1. power off all devices, leave mac battery disconnected
2. connect SPI clip to SPI header.
3. move switch to right position described above
4. power on the Pi, allow it to boot
5. connect the battery to the mac
6. connect the magsafe to the mac, wait a few seconds for startup
7. disconnect the magsafe from the mac, battery still connected
8. read/write with Flashrom

All that being said, my BIN file has some detail that I must have missed and is not fully booting.


Thanks again for any help the community can offer.

I hit more setbacks and little obstacles over the course of this 2 week project than I can even remember or that anyone would care to hear, but I did actually have fun learning about all of this so that counts for something.