According to kernel message on khadas VIM2 board equipped with BCM4356:
brcmfmac: brcmf_fw_alloc_request: using brcm/brcmfmac4356-sdio for chip BCM4356/2
usbcore: registered new interface driver brcmfmac
brcmfmac mmc0:0001:1: Direct firmware load for brcm/brcmfmac4356-sdio.khadas,vim2.txt failed with error -2
brcmfmac mmc0:0001:1: Direct firmware load for brcm/brcmfmac4356-sdio.txt failed with error -2
System needs the NVRAM file "brcmfmac4356-sdio.khadas,vim2.txt" to enable
the WiFi. After test, found it can share with the same file
"brcmfmac4356-sdio.vamrs,rock960.txt".