- SD/MMC Configration
Switch Default uSD/eMMC Routing: Arasan SDHCI -> EMMC2
http://mail-index.netbsd.org/port-arm/2021/08/08/msg007393.html
the Arasan SDHCI is used to connect bwfm(4).
bwfm0: Firmware file default: brcmfmac43455-sdio.bin
bwfm0: Firmware file model-spec: brcmfmac43455-sdio.Raspberry Pi 4 Model B.bin
bwfm0: Found Firmware file: brcmfmac43455-sdio.bin
bwfm0: NVRAM file default: brcmfmac43455-sdio.txt
bwfm0: NVRAM file model-spec: brcmfmac43455-sdio.Raspberry Pi 4 Model B.txt
bwfm0: autoconfiguration error: NVRAM file not available