Do i need the source tree to flash

Hello i’m going to build the optee repository remotely and i want to flash on my local computer. Do i only need the device/linaro/hikey/installer/hikey/ contents to flash?

Thanks

You may not even need that.
If your board already has the most recent bootloader and related parts installed, then what you need are out/target/product/hikey960/*.img files. Just fastboot flash them to the correct partitions.