Background

When tinkering with BIOS or for other reasons, if the Lattepanda board cannot boot, reflashing the BIOS is often a useful recovery solution.

This article uses the common CH341a programmer to reflash the BIOS firmware on the LattePanda 3 Delta as an example, detailing the specific steps.

Other models of LattePanda boards can also refer to this as the steps and methods are the same.

Preparation

Hardware

- LattePanda Board (e.g., LattePanda 3 Delta, LattePanda Mu, LattePanda Alpha)

- CH341a Programmer (can be purchased from platforms like Amazon)

- Wiring Cable

Software

- AsProgrammer

Download from https://github.com/nofeletru/UsbAsp-flash

- BIOS firmware

Can be downloaded from the Download Resource section of the LattePanda product Docs (https://docs.lattepanda.com/content/3rd_delta_edition/BIOS_Firmware_3_delta/) or GitHub repository (https://github.com/LattePandaTeam/LattePanda-Win10-Software/tree/master).

Driver

The downloaded AsProgrammer already contains the driver files for CH341A, located in the CH341-Drivers folder.

Double-click to run the installer to complete installation.

Wiring

The Flash chip for BIOS used in LattePanda is the W25Q series, with an operating voltage of 3.3V. The pin diagram is shown below:

On the LattePanda board, the pinout is presented same, as seen in the part with the BIOS silkscreen of the LattePanda 3 Delta's pin header.

The CH341A programmer supports two types of chips: 25 SPI BIOS and 24 I2C EEPROM. We use the programming pins from the 25 SPI BIOS part, which are often positioned and sequenced as illustrated below.

The actual position may vary slightly, so please refer to the silkscreen on the back of the programmer for accuracy.

Connect the pins from the 25 SPI BIOS part of the programmer socket to the pins of the LattePanda BIOS programming port.

CH341a Programmer Pins(25 SPI BIOS part)	LattePanda Pin Header(BIOS Part)
1	CS#
2	MISO
3	WP
4	GND
5	MOSI
6	CLK
7	HOLD
8	VCC (only 3.3V)

Attention: The BIOS Flash chip used by LattePanda operates at a voltage of 3.3V. If your programmer cannot provide a 3.3V operating voltage (such as only being able to provide 5V), do not connect the VCC pin(8th pin). In this case, simply power the LattePanda board, which will supply power to the BIOS Flash chip.

If your LattePanda board does not have a BIOS programming pin header but you can access the BIOS Flash chip, you will need to use a Flash chip clip to attach it directly to the Flash chip.

Reflashing Steps

Now we describe the reflashing process using the LattePanda 3 Delta BIOS firmware as an example.

1. Complete the wiring as described in the previous sections

Pay special attention to ensure that the BIOS Flash chip operating voltage is 3.3V.

2. Download the required BIOS firmware

Be careful of the model and version.

3. Open the AsProgrammer and set the relevant parameters

- Hardware: CH341A

- IC: For the LattePanda 3 Delta, the chip used is W25Q128JVSIQ, so select the path: IC->SPI->Winbond -> W25Q128JV

4. Click Open File to load the BIOS firmware(.bin)

5. Reflashing the BIOS firmware

Click the small triangle button next to the "Program IC" button. This will open a dropdown menu. Click to start reflashing.

Since the CH341a programmer writes a little slowly, please be patient as it may take more than 5 minutes.

6. Restart the LattePanda board after reflashing done

When the progress bar completes, it indicates that the reflashing was successful.

Then remove the connections, disconnect the power supply and RTC battery from the LattePanda board, wait 30 seconds, and then restart.

FAQ

Q. What is the model of the BIOS Flash chip for different LattePanda boards?

A. The LattePanda 3 and LattePanda Mu use the W25Q128JVSIQ, while the LattePanda Alpha uses the W25Q64JVSIQ.

Q. If I power the BIOS Flash chip directly with a programmer, will it activate other circuits on the board?

A. The 3.3V power goes through a diode before reaching the power pin of the BIOS Flash chip, which prevents reverse current flow. Therefore, powering the BIOS Flash chip with a programmer will not activate other circuits on the board.

Topics