I flashed the latest Armbian image from download page, upgraded to 5.76.190218 nightly Debian GNU/Linux 9 (stretch) 4.20.13-rockchip64, applied wireless fix from this thread (by copying firmware files), rebooted, but lsconfig just shows eth0. Here is the output of dmesg | grep -i sdio:
root@rockpi:~# dmesg | grep -i sdio
[ 1.711222] mmc0: new ultra high speed SDR104 SDIO card at address 0001
[ 5.545484] brcmfmac: brcmf_fw_alloc_request: using brcm/brcmfmac43455-sdio for chip BCM4345/9
[ 5.549768] brcmfmac mmc0:0001:1: Direct firmware load for brcm/brcmfmac43455-sdio.bin failed with error -2
[ 6.552057] brcmfmac: brcmf_sdio_htclk: HT Avail timeout (1000000): clkctl 0x50
Any idea what went wrong?