A1466 EMC2925 read issues


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3 years 2 weeks ago #4113 by reverendalc
i've got this A1466 EMC2925 macbook air from early 2015.

i've read the chip 7 times, and haven't had one matching md5sum.

flashrom identifies the chip, and everything works with no errors, but every read is different. assuming that's the case, i'm not comfortable trying to write to it either until i get this sorted out.

has anybody experienced this?

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3 years 2 weeks ago #4114 by CygnusX1
Replied by CygnusX1 on topic A1466 EMC2925 read issues
Hmm...... that is the first I have heard of that!?

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3 years 2 weeks ago #4115 by reverendalc
That's not what I want to hear!

Documentation tells me that's an MX25L6473E chip, and flashrom recognizes that as one of three possibilities.

I tried reading the chip with the 6406E definition and the other one... They all complete w/o error still, but no cohesive checksums.

This is dumb, I don't want to brute force it

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3 years 2 weeks ago - 3 years 2 weeks ago #4123 by CygnusX1
Replied by CygnusX1 on topic A1466 EMC2925 read issues
What 3 different chip ID's does flashrom find?

What is the command line you are using to get the readings?

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Last edit: 3 years 2 weeks ago by CygnusX1.

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3 years 2 weeks ago #4131 by reverendalc
i'm using:
flashrom -r /flashrom/efi/read1.bin -V -p linux_spi:dev=/dev/spidev0.0



that's the output, then i'm specifying:
-c MX25L6435E/MX25L6445E/MX25L6473E

i've read that this model is equipped with that chip, but i've also tried reads with the other options to no avail
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3 years 2 weeks ago #4135 by CygnusX1
Replied by CygnusX1 on topic A1466 EMC2925 read issues

reverendalc wrote: i'm using:
flashrom -r /flashrom/efi/read1.bin -V -p linux_spi:dev=/dev/spidev0.0



that's the output, then i'm specifying:
-c MX25L6435E/MX25L6445E/MX25L6473E

i've read that this model is equipped with that chip, but i've also tried reads with the other options to no avail


Here is the line I use to detect chips.
sudo flashrom -p linux_spi:dev=/dev/spidev0.0

Then to read your chip, I would use this command.
sudo flashrom -r ~/efi/read1.bin -V -p linux_spi:dev=/dev/spidev0.0,spispeed=8000 -c "MX25L6436E/MX25L6445E/MX25L6473E"

Then if you get a good read, use this command to write it back to the flash after you cleaned it up.
sudo flashrom -r ~/efi/read1.bin -V -p linux_spi:dev=/dev/spidev0.0,spispeed=8000 -c "MX25L6436E/MX25L6445E/MX25L6473E"


Let me know how that works.

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3 years 2 weeks ago - 3 years 2 weeks ago #4138 by reverendalc
well, i timed the read, it was a quick 15.59 seconds, but still...



much faster than w/o specifying spispeed... but no change in result. do you always set speed manually? i've never done that or had a problem w/o doing that.
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Last edit: 3 years 2 weeks ago by reverendalc.

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3 years 2 weeks ago #4140 by CygnusX1
Replied by CygnusX1 on topic A1466 EMC2925 read issues
Yes, I alway set my spi speed. I have never had a problem reading or writing with it set.
I need to think about what flashrom is doing while reading that chip.

reverendalc wrote: well, i timed the read, it was a quick 15.59 seconds, but still...



much faster than w/o specifying spispeed... but no change in result. do you always set speed manually? i've never done that or had a problem w/o doing that.


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3 years 2 weeks ago #4141 by reverendalc
can i always expect ~15sec reads and writes setting that speed?

that would be awesome in and of itself

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3 years 2 weeks ago #4143 by CygnusX1
Replied by CygnusX1 on topic A1466 EMC2925 read issues
yep! You sure can! :)

reverendalc wrote: can i always expect ~15sec reads and writes setting that speed?

that would be awesome in and of itself


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3 years 2 weeks ago #4144 by zenelli
Replied by zenelli on topic A1466 EMC2925 read issues
I had this problem too with 2015 mac air, all efi dumps are not the same so no good reading ( i think power Problem)
Solution taking out the chip

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3 years 2 weeks ago - 3 years 2 weeks ago #4147 by reverendalc

CygnusX1 wrote: yep! You sure can! :)


well shit on a biscuit. THAT should be part of the tutorial

@zenelli:

i assume it's power related also. i've got my pi powered by an ATX PSU, with 32A available LOL, but it seems enough of the MBA isn't being powered through that 12pin mezzanine connector. due to some recent frustration i've had with SMT, i'm reluctant to pull another chip lol
Last edit: 3 years 2 weeks ago by reverendalc.

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2 years 10 months ago #4786 by Chipset
Replied by Chipset on topic A1466 EMC2925 read issues
@ reverendalc

any results here?

regards

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2 years 10 months ago #4797 by reverendalc
unfortunately, successes with 2015 models have been mostly brute force and/or other methods.

it's unsafe and not recommended to use the raspberry pi on 2015+ models without removing the chip from the MLB.

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2 years 8 months ago #5801 by reignhell
Replied by reignhell on topic A1466 EMC2925 read issues
Hi,

I just to got the Easy Flash 4.03 and tried it on the same MBA early 2015, A1466 EMC2925. Getting the same result, MD5SUM does not match on 5 different reads. Anyone have any updates if possible to read/flash early 2015 MBA with RPi?

Thanks,

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2 years 8 months ago #5820 by reverendalc
The eifdL is supported and the recommended tool for these MacBooks.

You can brute force it, or remove the chip and program.

There are a few things you can try with the pi though.

Try removing the ssd and booting to the [?] screen. You should have the pi connected without the vcc pin. Attempt a read then.
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1 year 10 months ago - 1 year 10 months ago #8358 by smith.p.sean
I got this to work on my A1465 EMC 2924 by removing the VCC jumper from the pi.

BATTERY attached.
MAGSAFE attached.

Press power button to turn on mac. On chime, press and hold power button.

After screen blacks continue holding power button and start your reads. Hold power button until all 3 reads completed. Confirm MD5's. I got multiple good reads out of this method. Checksum would change if I stopped holding power button and started again but would remain the same as long as I held it down.
Took my first set of good looking dumps and removed $SVS information. Followed the same process to flash back on. Got several errors trying to write flash on :
sudo flashrom -w ./efi/new.bin -p linux_spi:dev=/dev/spidev0.0,spispeed=8000 -c "MX25L6406E/MX25L6408E"
flashrom v0.9.9-r1954 on Linux 4.9.41-v7+ (armv7l)
flashrom is free software, get the source code at flashrom.org

Calibrating delay loop... OK.
Found Macronix flash chip "MX25L6406E/MX25L6408E" (8192 kB, SPI) on linux_spi.
Reading old flash chip contents... done.
Erasing and writing flash chip...


Erase/write done.
Verifying flash...

FAILED at 0x00016000! Expected=0x80, Found=0xff, failed byte count from 0x00000000-0x007fffff: 0x18bc
Your flash chip is in an unknown state.
Please report this on IRC at chat.freenode.net (channel #flashrom) or
mail , thanks!



Continued flashing it until I got this :
sudo flashrom -w ./efi/new.bin -p linux_spi:dev=/dev/spidev0.0,spispeed=8000 -c "MX25L6406E/MX25L6408E"
flashrom v0.9.9-r1954 on Linux 4.9.41-v7+ (armv7l)
flashrom is free software, get the source code at flashrom.org

Calibrating delay loop... OK.
Found Macronix flash chip "MX25L6406E/MX25L6408E" (8192 kB, SPI) on linux_spi.
Reading old flash chip contents... done.
Erasing and writing flash chip... Erase/write done.
Verifying flash... VERIFIED.

Looking good to go.

SPS
Last edit: 1 year 10 months ago by smith.p.sean.
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11 months 2 weeks ago - 11 months 2 weeks ago #10374 by therion
Replied by therion on topic A1466 EMC2925 read issues
Sorry to say, although I havent posted much and am a N00b status, I can tell you efidl does not work on MBA 2015 no matter what tricks you try with power. You will get a read and an attempt at removal, but always a red light at the end. Im using the Pi 3b+ to read and edit the bin file, but after 10 reads I too cant get 1 md5 to match...
Last edit: 11 months 2 weeks ago by therion.

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11 months 2 weeks ago - 11 months 2 weeks ago #10375 by smith.p.sean
Follow my steps in the post above yours. Ask questions if something doesn't make sense to you and ill help ya. Just stating it doesn't work though is incorrect. I've done it several times now on this model.
Last edit: 11 months 2 weeks ago by smith.p.sean.

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