How to flash a Cheap Yellow Display

Check that it is a CYD

The model number ESP32-2432S028 is printed on the back of the board, next to the speaker connector. Boards with other numbers can look the same and use other screens and pins, so firmware for the CYD may not work on them.

Flash it

1. Count the USB ports. One micro-USB port is the ILI9341 variant. Micro-USB and USB-C side by side is the ST7789 variant. More in CYD with one USB and with two.
2. Open a project for this board and pick your variant in the Flash block.
3. Connect the board with a cable that carries data. Many phone charging cables only carry power, and the board will not show up with them.
4. Press Flash and pick the port. On Windows it is called USB-SERIAL CH340.
5. Wait until it finishes. The site downloads the firmware, checks its signature and checksums, writes it and verifies it. The firmware that was on the board is replaced.

The USB-C port on the two-port board does not work with USB-C to USB-C cables. Use micro-USB, or a cable with USB-A on the other end.

If it does not connect

• The port is not in the list: try another cable and another USB port, then install the CH340 driver.
• Failed to connect or it hangs on Connecting: hold BOOT, press and release RST, release BOOT, then press Flash again.
• Wrong boot mode detected (0x13): the board did not switch to its bootloader by itself. The same BOOT and RST buttons help. The CYD community guide also describes a hardware fix with a larger capacitor between EN and GND.
• The port is busy: close Arduino IDE, the PlatformIO serial monitor and any other program that may hold the port, then reconnect the board.
• Ubuntu and similar systems: remove the brltty service and add your user to the dialout group.

If the screen looks wrong after flashing

• White screen or wrong colors: you probably have the other variant. Flash the same project again with the other variant.
• Dark screen: press RST once. Then try another USB power source and another cable.
• GPIO21 drives the backlight. Keep anything you connected yourself off this pin.