Dell Latitude 5400 Bios password

[Alejandro Luo]

Have you removed the main battery and cmos battery ?

all battery had been removed and the cmos battery also

[hoaca388]

Hi everyone,

I’m trying to read (backup) the BIOS from a GigaDevice GD25Q256DYIG (3.3 V) on a Dell Latitude 5400 (LA-G892P, 2019).

My setup:

• CH341A (black), hardware-modded to output 3.3 V (because at 5 V it wouldn’t read).
• NeoProgrammer on Windows (the CH341A is detected fine).
• SOIC8 clip (to avoid desoldering).
• I also have a 1.8 V adapter (only to test behavior; I know the chip is 3.3 V).

Problem:

• With the CH341A plugged in, NeoProgrammer sees the programmer.
• The moment I clip onto the BIOS chip, Windows plays the USB-disconnect sound and the CH341A drops off the bus.
• If I insert the 1.8 V adapter, the USB doesn’t disconnect anymore, but of course the chip won’t read because it needs 3.3 V.

So far I’ve tried many things (different USB ports/cables, slower SPI speed in NeoProgrammer, etc.). My suspicion is a power/voltage/current issue or in-circuit loading from the motherboard.

Questions / Help wanted:

1. Has anyone seen this exact behavior (CH341A disconnects when clipping on at 3.3 V, but stays connected at 1.8 V) and found a fix?
2. Is this likely the motherboard back-feeding / overloading the 3.3 V rail when I inject 3.3 V from the CH341A?
3. Would you recommend isolating VCC (lifting pin 8) or just desoldering and reading off-board?
4. Do I need pull-ups on /WP and /HOLD, or any specific wiring tweaks for this model?
5. Any checklist to confirm proper pinout/contact on WSON-8 (if this package is WSON on this board), since a SOIC clip might not make good contact?

If someone had a similar case and solved it, I’d really appreciate your guidance. Thanks a lot!

Have you removed the main battery and cmos battery ?

[Alejandro Luo]

Hi everyone,

I’m trying to read (backup) the BIOS from a GigaDevice GD25Q256DYIG (3.3 V) on a Dell Latitude 5400 (LA-G892P, 2019).

My setup:

• CH341A (black), hardware-modded to output 3.3 V (because at 5 V it wouldn’t read).
• NeoProgrammer on Windows (the CH341A is detected fine).
• SOIC8 clip (to avoid desoldering).
• I also have a 1.8 V adapter (only to test behavior; I know the chip is 3.3 V).

Problem:

• With the CH341A plugged in, NeoProgrammer sees the programmer.
• The moment I clip onto the BIOS chip, Windows plays the USB-disconnect sound and the CH341A drops off the bus.
• If I insert the 1.8 V adapter, the USB doesn’t disconnect anymore, but of course the chip won’t read because it needs 3.3 V.

So far I’ve tried many things (different USB ports/cables, slower SPI speed in NeoProgrammer, etc.). My suspicion is a power/voltage/current issue or in-circuit loading from the motherboard.

Questions / Help wanted:

1. Has anyone seen this exact behavior (CH341A disconnects when clipping on at 3.3 V, but stays connected at 1.8 V) and found a fix?
2. Is this likely the motherboard back-feeding / overloading the 3.3 V rail when I inject 3.3 V from the CH341A?
3. Would you recommend isolating VCC (lifting pin 8) or just desoldering and reading off-board?
4. Do I need pull-ups on /WP and /HOLD, or any specific wiring tweaks for this model?
5. Any checklist to confirm proper pinout/contact on WSON-8 (if this package is WSON on this board), since a SOIC clip might not make good contact?

If someone had a similar case and solved it, I’d really appreciate your guidance. Thanks a lot!

[BIOSSASI]

Anyone Who Need CLEAR ME For "DELL LATITUDE 5400 EDC41 LA-G892P REV 1.0 32MB"
Enjoy
Patched BIOS Only For EDC41 LA-G892P REV 1.0 32MB
Again Confirming This is Only For 32MB ( 32,768 KB )

01.Flash
02.Connect Power Adaptor & The Flashing ME will be start Automatically.

Some Updated ME will Directly Boot ! Dont Worry

NO DELAY BOOT , NO HANGS , NO BUGS !!!
Have a great Day !

Sure ! sorry , Mistakenly Posted as a new topic. Thank You.

[Kinshir]

Hello again,

Is there a way to check if a Dell Bios .bin file is corrupted or any tool for this matter?

Thank you very much!

[peste]

Anyone Who Need CLEAR ME For "DELL LATITUDE 5400 EDC41 LA-G892P REV 1.0 32MB"
Enjoy
Patched BIOS Only For EDC41 LA-G892P REV 1.0 32MB
Again Confirming This is Only For 32MB ( 32,768 KB )

01.Flash
02.Connect Power Adaptor & The Flashing ME will be start Automatically.

Some Updated ME will Directly Boot ! Dont Worry

NO DELAY BOOT , NO HANGS , NO BUGS !!!
Have a great Day !

post S/N, full name and model, motherboard model,TYPE,etc.

[peste]

post merged..next time look for a thread with the name and model, motherboard model of the laptop, and post there, if you can't find it, then make a new thread..

[BIOSSASI]

Anyone Who Need CLEAR ME For "DELL LATITUDE 5400 EDC41 LA-G892P REV 1.0 32MB"
Enjoy
Patched BIOS Only For EDC41 LA-G892P REV 1.0 32MB
Again Confirming This is Only For 32MB ( 32,768 KB )

01.Flash
02.Connect Power Adaptor & The Flashing ME will be start Automatically.

Some Updated ME will Directly Boot ! Dont Worry

NO DELAY BOOT , NO HANGS , NO BUGS !!!
Have a great Day !

[Kinshir]

Hello you can try this new build bios from your corrupt original bios good luck ....

Hello and thank you very very much,

This last build worked, I managed to push it to the laptop and did a double verification and it started and it works.
What did you do, how did you do?

Thank you very much!

[g_george_n]

One more thing, I know how to remove the chip from the board, but I'm asking you guys because you're specialists and I don't want to ruin them.

[g_george_n]

Hello Everyone, I have 8 dell Latitude 5400 laptops, Example: SERVICE TAG(S/N): 9L7K5Y2
MFG YR:2019
20873528858
EXPRESS SERVICE CODE.

Beg Model/z: P98G
Reg Type No.. P98G001, the question is, can I find someone to help me privately to find out the bios password? including telling me which bios reader to buy, I am willing to contribute with a donation to the forum. Thanks, George

[Markus1741]

Hello,

I wrote the BIOS on the chip using the WSON8 probe, verified it twice but still the same behavior.
I don't have knowledge of soldering to try and unsolder it, but I suspect that I might have damaged the chip connections to the motherboard with the probe, hence I will try with a local service to have it checked.
I'm attaching two pics of the BIOS chip for your opinion.


Thank you very much for all the help.

Hello you can try this new build bios from your corrupt original bios good luck ....

[Kinshir]

Hello,

I wrote the BIOS on the chip using the WSON8 probe, verified it twice but still the same behavior.
I don't have knowledge of soldering to try and unsolder it, but I suspect that I might have damaged the chip connections to the motherboard with the probe, hence I will try with a local service to have it checked.
I'm attaching two pics of the BIOS chip for your opinion.


Thank you very much for all the help.

[LBTT1121]

Hello,

I tried to remove the BIOS password on my Dell Latitude 5400 using the patcher.
Got a the bios dump with the programmer
And unlocked it with the patcher

But now whether I upload the initial dump or the unlocked dump, when I connect the power, the front led is white, the power button and the keyboard lights up for 1-2 seconds, the fan also starts for 1-2 seconds and it keeps repeating.
Please help.

Service Tag: J9XQ433
Board: LA-G891P

Thank you very much!

try and feedback

[Kinshir]

You copied the bios with errors.
The bios chip must be unsoldered from the board before writing or reading..
do not use the clip, you may have errors..if you do not have anything to unsolder it with,
solder wires between the programmer and the bios chip..
.here is a video for example..https://www.youtube.com/watch?v=DWWi...nnel=ThisIsHow

I understand, but since I copied the original BIOS with errors, after I unsolder it, what BIOS I should write on it?
Can you help me with a suggestion?

Thank you!

[peste]

Hello,

I tried to remove the BIOS password on my Dell Latitude 5400 using the patcher.
Got a the bios dump with the programmer
And unlocked it with the patcher

But now whether I upload the initial dump or the unlocked dump, when I connect the power, the front led is white, the power button and the keyboard lights up for 1-2 seconds, the fan also starts for 1-2 seconds and it keeps repeating.
Please help.

Service Tag: J9XQ433
Board: LA-G891P

Thank you very much!

You copied the bios with errors.
The bios chip must be unsoldered from the board before writing or reading..
do not use the clip, you may have errors..if you do not have anything to unsolder it with,
solder wires between the programmer and the bios chip..
.here is a video for example..https://www.youtube.com/watch?v=DWWi...nnel=ThisIsHow

[Kinshir]

Hello,

I tried to remove the BIOS password on my Dell Latitude 5400 using the patcher.
Got a the bios dump with the programmer
And unlocked it with the patcher

But now whether I upload the initial dump or the unlocked dump, when I connect the power, the front led is white, the power button and the keyboard lights up for 1-2 seconds, the fan also starts for 1-2 seconds and it keeps repeating.
Please help.

Service Tag: J9XQ433
Board: LA-G891P

Thank you very much!

[Lover1abd]

3.4. Dell

Dell laptops store the password in EC. However, some generators exist depending on the code suffix.
See: https://beta.bios-pw.org/ .If the website is offline try: https://web.archive.org/web/*/https://bios-pw.org/
Note: All passwords must be entered with a US QWERTY Keyboard,you can use a USB one.
Note: The 6FF1 suffix has a bug,use your service tag with the 1F5A or BF97 suffix instead,Example: 1234ABC-BF97 .
Note: The list of examples does not include some other suffix codes that do work,such as E7A8 .
Note: If the BF97 suffix does not work try it with the E7A8 suffix instead.
Note: There is no publicly available 8FC8 generator available at the moment.
The CTRL-ENTER-ENTER keystroke after the password only applied to laptops with a suffix (xxxxxxx-8FC8 for example), until Dell also required it in some laptops using System Disable 16-Hex algorithm, on which only the Password+ENTER was needed at first and then in some models you needed the CTRL-ENTER-ENTER to properly delete the system passwords, otherwise the password would remain SET upon the automatic system reboot if just doing Password+ENTER until the proper CTRL-ENTER-ENTER keystroke was performed in certain models.
8FC8 Patcher software: https://www.badcaps.net/forum/troubl...l-8fc8-patcher

Actually its does works
With dell patcher but i had to wipe the chip first
Thank you so much

And thanks for everybody for helping me

[Lover1abd]

At first boot press F2, write your Service Tag, disable Absolute if it was activated, Save and Exit.

Only power light with no display

Could be chip went bad ????

[Lover1abd]

hi try

After flashing no display