Flashing AM4 BIOS with CH341

[Peter_1402]

Hi,

Is it impossible to flash Asus TUF B450M-Plus Gaming BIOS(25LB128D) with CH341? I have done it with H270N BIOS.
I used NeoProgrammer and selected 25LQ128C IC since 25LB128D is not in the chiplist.dat. I get no response from IC.
Any expert can help on setting up the import.xml so that I can import 25LB128D into chiplist.dat.

Thanks in advance.

[m1ch43lzm]

You also need an additional 1.8V adapter like the one pictured when using CH341A, all Ryzen boards use 1.8V BIOS chips

Selecting GD25LQ128C_1.8V should work

[Peter_1402]

@m1ch43lzm, Thanks. I have a CH341A and it voltage selector switch. I selected 1.8V. When I click detect on NeoProgrammer, the LED turn green momentarily and turn red.

[m1ch43lzm]

Are you using a clip or desoldered the chip from the board
If using clip, try removing CPU from socket
It's best to desolder the chip
Also try with AsProgrammer
https://github.com/nofeletru/UsbAsp-flash/releases

[Peter_1402]

@m1ch43lzm, I managed to program the BIOS chip with Rev 4622. But the USB device over current still there. I have to remove the bad ESD protection chip which is still on the motherboard.

[m1ch43lzm]

https://www.badcaps.net/forum/troubl...rrent-detected
https://www.badcaps.net/forum/troubl...nt-modded-bios

Boardview
https://www.badcaps.net/forum/troubl...ing-schematics

Hardware problem, maybe something wrong with USB_OC signals, check the area marked with a red circle
PM_USB_OC_x
S_USB_OC__ALL
USB_OC_12
USB_OC_3456

[Peter_1402]

@m1ch43lzm, Thank you very much for your tips. I will look into it. But first, please help comment on my findings. I just learn how to use boardviewer. 😁 I measured +5V for UD5 and OD400 and both showing ~4.5V. Can the low voltage triggered the USB device over current detection?

[m1ch43lzm]

Use FlexBV Free https://www.badcaps.net/forum/troubl...acos-and-linux
UD5 is on the USB data lines, OD400 is on the PS/2 keyboard data lines; the USB overcurrent detection is somewhere else
Maybe check at pin 3 of UD700, S_USB_OC__ALL, and back track from there

[Peter_1402]

@m1ch43lzm, I will look into it and get back to you. Thank you very much.

[Aliencomputres]

@m1ch43lzm, I managed to program the BIOS chip with Rev 4622. But the USB device over current still there. I have to remove the bad ESD protection chip which is still on the motherboard.

remove the bios battery or better yet, desolder the bios chip and reprogram it.

[Peter_1402]

Aliencomputres, I downgrade to 4604 and still no good. So, it's not BIOS issue. Thanks.

@m1ch43lzm, I have looked at UD700 and having a hard time tracing. The is no UD64 in the motherboard. Is this normal?
Before coming to Badcaps, I have removed UD6, UD7, UD21 and UD24. I stop at UD24 because the PC booted up OK. But the problem came back the next day.
These are SOT23 6pin IC aka ESD protection diodes / TVS diodes. All these chip have Asus internal marking. Any idea which part I can buy to replace them?
Thanks.

[m1ch43lzm]

Aliencomputres, I downgrade to 4604 and still no good. So, it's not BIOS issue. Thanks.

@m1ch43lzm, I have looked at UD700 and having a hard time tracing. The is no UD64 in the motherboard. Is this normal?
Before coming to Badcaps, I have removed UD6, UD7, UD21 and UD24. I stop at UD24 because the PC booted up OK. But the problem came back the next day.
These are SOT23 6pin IC aka ESD protection diodes / TVS diodes. All these chip have Asus internal marking. Any idea which part I can buy to replace them?
Thanks.

Did you try the modded 4622 BIOS from here: https://www.badcaps.net/forum/troubl...nt-modded-bios
It's in .cap format, so should be possible to flash via USB with EZ-Flash

Those diodes you removed are unrelated, those are protection for the data lines (D+, D-), the actual issue with "overcurrent" is related to the 5V power supply to the USB ports

Measure voltage on pin 3 of UD700, you should have around 3.3v there
Check this video about USB overcurrent detected (it's in spanish, I haven't found a similar one in english yet) https://www.youtube.com/watch?v=FCHFMEJflbE
What he does in the video, is checking if the 5V is present on all the USB ports (including front panel USB), and he's also checking the voltages at the resistor packs that are connected to the 5V pins of the USB ports, he also explains that the circuits may vary, but the overcurrent detection signal goes to the chipset (he calls it "PCH" on AMD... but he's right) in the end
In his first board, it was a blown resistor (the diode was missing from factory), as the signal didn't reach the chipset (exact same ball on the chipset, S_USB_OC__ALL, as his board is another ASUS B450)
The next board he shows quickly (around 16-17min), it was a signal that goes to the AMD CPU socket, in your board it's related to SU3 and SU4 ICs
It depends where the fault is, whether it's related to the B450 chipset USB ports, or the CPU USB ports

On the boardview, start at the 5V pins of the USB ports, click on it, then it will show where that goes, follow it until you find a resistor, diode, resistor pack, and depending on which ports are "faulty", it will either end at the chipset or the CPU socket

Example: Click on pin 1 of U31G2_1 (the USB port stacked on top of the Type-C port), the 5V go to UCR196, after that it goes to UCD323, then it goes on pin 3 to a voltage divider conformed by UCR197 and UCR198, then goes all the way to the chipset at S_USB3D1_OC_1
I'ts tedious work for sure to track each signal, so if any of those signals is missing, you get the "overcurrent" error

I don't know if UD64 is supposed to be missing, as I don't have a working board of the same model to check, sometimes they design the parts to be there, but the final version doesn't have those parts fitted from factory, it happens a lot in laptop boards
For the ESD diodes, you may ask in the General Electronics Technical Discussion section, with close-up pictures of the markings of the diodes themselves (assuming you haven't lost them), or this thread in the laptop section: IC Marking Codes and Datasheets #2
Someone there may help identifying the part number from the markings, as it's not listed in the boardview currently available

[Peter_1402]

@m1ch43lzm, Thank you for your reply. I couldn't ask for more. I can proceed with the debug now.