Unable to read chip - competitor clip

Hey all,

The mac I'm trying to get into is a A1502 EMC2678. I've got the RebelSim clip and it seems to clip onto the port just fine.
Attached is my setup, I've gotten FlashRom installed correctly on my Rasperry Pi. I've double checked to make sure that SPI is enabled.
The error I get when I runis "No EEPROM/flash device found"
Seems like my wires are mismatched or something. I believe that I have the right GPIO config, triple checked it.

Not sure what else I am missing.

Any help is greatly appreciated.

Yeap, I've tried the switch in the other position and rebooting the Pi

There is probably not going enough power from the pi to the chip. Do you use original power cord to power up the raspberry?

I've had power issue's before. Sometimes there is some capacitor dropping the voltage causing not enough power going to the chip. What you can try is connecting a 85 watt charger to the board and than read out the chip. When you connect the charger without battery it powers the board on automaticcaly. Make sure you turn of the board with the charger on the board before you read the chip.

Bigwezel wrote: There is probably not going enough power from the pi to the chip. Do you use original power cord to power up the raspberry?

I've had power issue's before. Sometimes there is some capacitor dropping the voltage causing not enough power going to the chip. What you can try is connecting a 85 watt charger to the board and than read out the chip. When you connect the charger without battery it powers the board on automaticcaly. Make sure you turn of the board with the charger on the board before you read the chip.

I was using a cell phone charger, but I switched to the stock CanaKit 5v @2.5a charger and still nothing. I connected the magsafe charger with the battery disconnected. Then I turned it off using the power button, connected the chip, and still no read.

thaGH05T wrote: Yea, please test your voltage, the purpose of this clip is to not remove the logic board, and usually when we conduct a flash with it we are connecting the battery and sometimes magsafe to counteract the capacitors and/or resistors that may be causing the drop in your case. Use the maximum rated power supply recommended for your pi to help reduce loss on the Pi's end. Your wires seem to be short enough so let us know what your next tests hold.

How do I test my voltage?I've tried it with the battery connected, no magsafe, then added the clip. then tried with battery and magsafe then added clip and nothing. I've attached the clip then added the magsafe and tried to read. Nothing

there must be a difference in pinout on the port of the motherboard. while that page lists the device for 2010-2014, the list of supported models shows the earliest compatible hardware revision as a1369 which is a 2011 model. i would guess the following:

rebelsimcard is dumb
rebelsimcard is complacent
rebelsimcard is scamming

Hi. This thing is simply doesn't work. I've got a locked EFI and locked SSD on MBA Mid-2013. Also tried it on later models, same result. Not mentioning that current models have different smaller connector, which makes this device useless on them. Once I try to access Bus Pirate to read the chip type, the machine switches off and the chip appears to be unreadable. And to read it without having the machine powered on is impossible because it doesn't supply enough power to the chip. I even tried external power supply through separate breadboard. It works on some older models, but on Mid-2013 onwards it doesn't work. Had a client who bought machine on eBay and when it's arrived, it appeared to be locked. Apple wished him good luck and suggested to be more careful next time. So, he called me. I checked the connector, and being armed with my can do attitude, as an idiot assured him that this is not a problem:) And that was a major fk up from my part...
Anyway, I will be really appreciated if when there's normal 8-pin edition for sale, please let me know immediately. I think, supplying additional power through pin 7 might help. Or any other working solution. Because latest models require more power, or EFI chip desoldering. I might have to remove the chip and try to reprogram it separately. Unfortunately, this device appeared to be useless to me. This is the second 2013 model which doesn't allow to be reprogrammed with that thing:/

Hi. Ok, It's definitely a clip problem. I've got MBA 11 Mid-2013 and had to open my own MBA 13 Mid-2013 to check this thing out. Even with external power it drains the power out of the machine. Once connected and switched on, both machines are shutting down. When I disconnect the clip, they power on back again. I've tried switching pins, provide additional power through Arduino Power supply with switcheable v3.3 and V5. Same result. It gives me a strong feeling that power escapes through somewhere when the clip is connected. I also tried Raspberry Pi 2 with the same result. In fact I prefer Bus Pirate because it was able to write chips that I was unable to write with Raspberry sometimes. But this is just a matter of preference, I think.
Maybe the circuit is shorted? The leakage is so bad that no matters if the computer is powered on, with or without battery connected or even with 45W/60W Power supply in, same result.
Any suggestions? I had like two clients already and I really would like to avoid de soldering the chip and do it old school style. Also, I think it would go better with normal 8 pin clip when there's no switchable or hardwired pins, because it gives more control.

Thanks.

The reason it doesnt work on certain models is becuase the eeprom is not getting power - thats why it sometimes you need the battery or magsafe or need it running. Also why you sometimes get a dump that starts with data and the rest is blank. Sometimes the eeprom gets power from PP3V3_SUS and sometimes its PP3V3_SUS_ROM. Helps to check the schematics.

sergioz wrote: Hi. Ok, It's definitely a clip problem. I've got MBA 11 Mid-2013 and had to open my own MBA 13 Mid-2013 to check this thing out. Even with external power it drains the power out of the machine. Once connected and switched on, both machines are shutting down. When I disconnect the clip, they power on back again. I've tried switching pins, provide additional power through Arduino Power supply with switcheable v3.3 and V5. Same result. It gives me a strong feeling that power escapes through somewhere when the clip is connected. I also tried Raspberry Pi 2 with the same result. In fact I prefer Bus Pirate because it was able to write chips that I was unable to write with Raspberry sometimes. But this is just a matter of preference, I think.
Maybe the circuit is shorted? The leakage is so bad that no matters if the computer is powered on, with or without battery connected or even with 45W/60W Power supply in, same result.
Any suggestions? I had like two clients already and I really would like to avoid de soldering the chip and do it old school style. Also, I think it would go better with normal 8 pin clip when there's no switchable or hardwired pins, because it gives more control.

Thanks.

I'm having the same problem. I turn on the mac and wait for the folder to start flashing. Once I connect the clip on the board it cuts out. Immediately the mac chime plays when I remove the clip. I am using a 5v @ 2.4a for the pi, and a 85W 20v @ 4.25a charger for the mac. I've tried it with the battery connected only, battery and magsafe, magsafe only. All the same results where the mac gets powered off with the clip on the board. I am thinking, should I get higher output power cables for the mac and pi?

neighborhoodguy wrote: The reason it doesnt work on certain models is becuase the eeprom is not getting power - thats why it sometimes you need the battery or magsafe or need it running. Also why you sometimes get a dump that starts with data and the rest is blank. Sometimes the eeprom gets power from PP3V3_SUS and sometimes its PP3V3_SUS_ROM. Helps to check the schematics.

Excuse my ignorance, how would checking the schematics help? To find either if PP3V3_sus or PP3V3_SUS_ROM need to be powered? When I have battery and magsafe in, AND turn it on, it still cuts out once I connect the clip.

rav wrote:

I'm having the same problem. I turn on the mac and wait for the folder to start flashing. Once I connect the clip on the board it cuts out. Immediately the mac chime plays when I remove the clip. I am using a 5v @ 2.4a for the pi, and a 85W 20v @ 4.25a charger for the mac. I've tried it with the battery connected only, battery and magsafe, magsafe only. All the same results where the mac gets powered off with the clip on the board. I am thinking, should I get higher output power cables for the mac and pi?

The MacBook should not be turned on / running while the pi is connected.

When I first got a clip I couldn't get it to work half the time so I started looking at the schematics, in order to understand why it seemed so hit and miss.

For example - the vcc line of your clip doesn't go to the eeprom's vcc line

Yes - I've had the same experience - they shut off when you connect the clip - so you can't power it that way. Sometimes i run a 3.3v line off my clip to pin 8 of the eeprom. If you check pin 8 with a voltmeter you'll see it go up and down according to power states.

Is it convenient? NO.

Yesterday I did two 2010 13" airs, both emc 2392 (820-2838-a). seemed to work if i connected clip, then ac, then removed ac. I'm using a ch341 based programmer.

we all need to start thoroughly documenting specific models and the power states that they've been successfully flashed in.

i've personally flashed a MacBook with the machine powered on too