Hacking Hardware emmc slower mode (200 MB/s) - hwfly V5

[Crypto900]

Hi

I just installed the hwfly v5 chip to my new switch oled and run into an issue.
My emmc init fails and it falls back to slower mode and works fine with a 200MB/s connection.

My emmc should be totally fine and working. I think its the wires from point C and/or B (I used very thin coated copper wires from an old FAN which are probably 0.1mm).
I also lost the B point on the hwfly chip itself and soldered it onto a very very very little dot which was left from under where the pad was.

I found a closed issue on Hektate GitHub where they added the slower mode and talk about bad wires, length and signal interferences.
I could create a sysnand backup and extracted the keys.

the emmc chip got not reflowed, I put it under, fixed it with anchor points and it got the right values. I don't think its the emmc itself.

Now my question:
Does this issue comes from wrong wires? Or does this come from a probably bad B point on the hwfly chip?
Is there any alternative point where I can solder the B point on the hwfly v5 chip?

I purchased alternative wires with 0.1mm, they look basically the same as the ones I got out of the old fan. So I don't know if its worth the replacement. I think I should first check that B point on the hwfly chip.

Update:
I already tried replacing the wires from C and B with new 0.1mm coated copper wires and routed them around so they get as less interferences as possible.
still get the same issue.

How should I proceed to fix this issue?

Many thanks!

 

[Hayato213]

You might need an new emmc in which you can try the following

There are 2 way to retrieve it

First method

1. Try to recover the prod.keys with lockpick.rcm and try to backup boot0/1 if possible
2. Get a switch emmc from ali (OR try to reflow the emmc with flux and 400 degree after disconnecting it fully from the switch) *do not use hot air direct inside the switch, take out the emmc to a heat resistant mat * Then wait 5 min before putting the emmc back in, try hekate again to see if you can init the emmc
3. If reflowing does not work, use emmchaccgen to generate prod.keys with matching firmware version ( can be seen from hekate fuse count)

Second Method.

1. Buy a switch emmc from ali
2. You need a working donor prod.keys + donor raw nand then use your half broken prod.keys to sign the DONOR nand
3. Require NxNandmanager to sign the DONOR raw nand
4. Then use hekate to restore it to your emmc

Second method takes a bit of work like 3 to 5 hour and will not have a working serial number because it is created with a half broken prod.key

 

[Crypto900]

It’s a switch oled, so it’s not possible to unplug the emmc like on the older models.

So you think it’s a faulty connection on the emmc chip?

I waited to reflow, wanted to get some knowledge from here first, if the issue is the emmc chip/connection or some other issue.


I made a Backup of the full emmc and also saved the prod.keys.
I have a full backup of boot0 and boot1.

 

[Hayato213]

It’s a switch oled, so it’s not possible to unplug the emmc like on the older models.

So you think it’s a faulty connection on the emmc chip?

I waited to reflow, wanted to get some knowledge from here first, if the issue is the emmc chip/connection or some other issue.


I made a Backup of the full emmc and also saved the prod.keys.
I have a full backup of boot0 and boot1.

You going have to get a new 64GB eMMC Storage chip and resolder it.

 

[Crypto900]

Does the stock firmware boot with this issue?
Because the stock firmware worked a few days ago with added emmc dat0 chip slipped under.

I have to check if I can get the stock firmware to still boot or if the issue appeared while installing the HWFly v5…

Probably a reflow could fix it.

 

[Hayato213]

Does the stock firmware boot with this issue?
Because the stock firmware worked a few days ago with added emmc dat0 chip slipped under.

I have to check if I can get the stock firmware to still boot or if the issue appeared while installing the HWFly v5…

Probably a reflow could fix it.

I assume stock won't boot since it is sysnand.

 

[Crypto900]

Yea I tested it. Stock boot does not work anymore.
Booting through rcm does work for sysnand (and emummc).


I just tried reflowing the emmc, no change, same error.
I still don't think its the emmc chip or its connection, because it worked 2 days before and was untouched since then.

Can any other component relating to the hwfly setup cause this?

what does sdmmc4 mean? there is sdmmc1-4. what does 4 exactly mean?

can it be the cmd resistor? I read the cmd resistor can also cause emmc init failures (if that resistor gets completely broken, it produces a purple screen and emmc init failures too) or any other point where the modchip got added?

I can't imagine the emmc chip which worked 2 days ago untouched till now suddenly breaks.

Post automatically merged: Mar 13, 2023

I probably found the issue, I don't think those two should be connected together, right?

CMD capacitor is connected with the beside one.

 

[Hayato213]

Yea I tested it. Stock boot does not work anymore.
Booting through rcm does work for sysnand (and emummc).


I just tried reflowing the emmc, no change, same error.
I still don't think its the emmc chip or its connection, because it worked 2 days before and was untouched since then.

Can any other component relating to the hwfly setup cause this?

what does sdmmc4 mean? there is sdmmc1-4. what does 4 exactly mean?

can it be the cmd resistor? I read the cmd resistor can also cause emmc init failures (if that resistor gets completely broken, it produces a purple screen and emmc init failures too) or any other point where the modchip got added?

I can't imagine the emmc chip which worked 2 days ago untouched till now suddenly breaks.

Post automatically merged: Mar 13, 2023

I probably found the issue, I don't think those two should be connected together, right?

CMD capacitor is connected with the beside one.

Shouldn't be touching each other.

 

[Donnie-Burger]

Hi

I just installed the hwfly v5 chip to my new switch oled and run into an issue.
My emmc init fails and it falls back to slower mode and works fine with a 200MB/s connection.

My emmc should be totally fine and working. I think its the wires from point C and/or B (I used very thin coated copper wires from an old FAN which are probably 0.1mm).
I also lost the B point on the hwfly chip itself and soldered it onto a very very very little dot which was left from under where the pad was.

I found a closed issue on Hektate GitHub where they added the slower mode and talk about bad wires, length and signal interferences.
I could create a sysnand backup and extracted the keys.

the emmc chip got not reflowed, I put it under, fixed it with anchor points and it got the right values. I don't think its the emmc itself.

Now my question:
Does this issue comes from wrong wires? Or does this come from a probably bad B point on the hwfly chip?
Is there any alternative point where I can solder the B point on the hwfly v5 chip?

I purchased alternative wires with 0.1mm, they look basically the same as the ones I got out of the old fan. So I don't know if its worth the replacement. I think I should first check that B point on the hwfly chip.

Update:
I already tried replacing the wires from C and B with new 0.1mm coated copper wires and routed them around so they get as less interferences as possible.
still get the same issue.

How should I proceed to fix this issue?

Many thanks!

Problem with your install 100%.

 

[Crypto900]

I managed to desolder it and separate them again.
But that was not enough.
It turns out that my cmd resistor (4k7 ohm) also was corrupted, probably got too hot.
After separating the resistors again, I always got „emmc init failed“. So it was completely dead.

I harvested the resistor from a dead switch v2 Mainboard and replaced it in my oled.

Now everything works again and emmc is back at 400 MB/s speed.

Thanks for your support here.

This was truly a journey for my first time micro soldering. But it was also fun and a good learn curve.
I practiced a day with hot air removing and soldering 0201 resistors/capacitors and similar on a dead board till I got a feeling and some secureness with it.