This board is Similar to the NanoPi R2S (same specs) and should boot with the NanoPi R2S uboot. Only the leds are on different pins and not yet working.
The Orange Pi R1 Plus LTS is a FriendlyElec mini-router with edge-computing and dual Gbps Ethernet ports.
IPFire using the Serial Port at baud rate of 115200 n8. The R1 Plus connects via a 3.3V TTL, 3-pin 2.54mm pitch connector.
Download ipfire (aarch64) from here and verify the sha256 checksum.
xzcat ipfire-2.27.2gb-ext4.aarch64-full-core165.img.xz > /dev/mmcblk?
# (or /dev/sd? depends on you cardreader)
Mount the boot filesystem (1 Partition) and edit uENV.txt:
fdtfile=rockchip/rk3328-orangepi-r1-plus.dtb