Banana Pi BPI-R4 Review: Wi-Fi 7 OpenWrt Router board with dual SFP+ ports

Making a UART Serial extension cable.

The primary goal of this arrangement is to facilitate external access to the board’s UART serial headers without the need to remove the upper cover of the case. This is accomplished by incorporating a female HX2.54 3-Pin connector into the pre-existing rectangular cutout in the R4 metal case.

The upper case fits securely into the lid of the case, but it really makes it incompatible to open repeatedly. This becomes particularly challenging when flashing the operating system onto the board’s SPI/eMMC flash chips when you need access to the R4 board serial port. To address this issue, we carefully cut and soldered two varieties of wire: one featuring an HX2.54 3-pin connector and the other equipped with a 2.54mm 3-pin connector that will fit perfectly with the R4 UART header pins.