Download the utility sunxi-fel to your computer (Mac OS is not supported) and download the CB1 driverFor windows download sunxi-fel.exeFor linux download sunxi-fel-aarch64For arm download sunxi-fel-armhf
Push the DIP switch (USB OTG) and (RPI BOOT) to ON to enter BOOT mode.As shown in the following figure is for PI4B_Adapter.For other motherboards, refer to the CM4 eMMC part of the motherboard manual to set the switch.For some motherboards (e.g. Manta-E3EZ, Manta-M8P-V1.1, Manta-M5P) with OTG/UART selector switch for Type-C, we also need to set the switch to OTG mode according to motherboard's manual
USB driver for windows (Linux skip this step): refer to the official website of AllWinner
Download Zadig to the rescueEnable Options->List All Devices Select the USB device to install the driver(most likely will be "unknown"). Make sure the device USB ID is "1F3A:EFE8"). Click Install Driver after confirming that the information is correctOpen the Powershell(windows) or console terminal(linux) where you downloaded the sunxi-fel tools and CB1 driver in step 1.
Run.\sunxi-fel.exe -v ver (windows)sudo ./sunxi-fel-armhf -v ver (linux-armhf)sudo ./sunxi-fel-aarch64 -v ver (linux-aarch64)to check whether the USB of CB1 is connected normally.If you get ERROR: Allwinner USB FEL device not found! means that the USB is not recognized. Please recheck whether the driver is installed successfully.If you get AWUSBFEX soc=00001823(H616) means that CB1 eMMC is ready.
Here on the first line is an example of error you will see if the driver did not install correctly.On the second line is an example of what it will look like after zadig has installed the driver correctly.
Run.\sunxi-fel.exe uboot .\u-boot-sunxi-cb1-emmc.bin (windows)sudo ./sunxi-fel-armhf uboot ./u-boot-sunxi-cb1-emmc.bin (linux-armhf)sudo ./sunxi-fel-aarch64 uboot ./u-boot-sunxi-cb1-emmc.bin (linux-aarch64)to write u-boot to CB1
When the uboot is written, the computer will recognize a USB flash disk, and then you can use balenaEtcher or Raspberry Pi Imager to write the OS image to eMMC. The steps are the same as the SD card version.
Refor to Overlays Settings to set fdtfile to sun50i-h616-biqu-emmc