nerves_system_openwrt_one

# U-Boot environment configuration for the OpenWRT One
#
# Two redundant ubootenv UBI volumes on SPI NAND. The C tool fw_printenv
# (from u-boot-tools) and the Erlang `uboot_env` library used by
# Nerves.Runtime.KV both read this file. Both implementations agree on
# the CRC format so values written by one can be read by the other.
#
# Format: device_path  offset  env_size  flash_sector_size  num_sectors
#
# - device_path: the UBI volume character devices. We use /dev/ubi0_N
#   (the per-volume nodes) instead of the /dev/ubi0:<name> syntax that
#   only the C tool understands -- the Erlang `uboot_env` library opens
#   the path with File.open and needs a real file, not a "find by name"
#   shorthand. The C tool happily accepts /dev/ubi0_N too, so both
#   implementations end up reading the exact same volume.
# - offset:      always 0 for UBI volumes (the volume itself starts at 0)
# - env_size:    0x1F000 (126976) -- MUST match CONFIG_ENV_SIZE in
#   OpenWrt's mt7981 U-Boot (the one loaded from our `fip` volume).
#   The env we bake includes the full OpenWrt default env (bootcmd,
#   boot_*, ubi_*, bootmenu_*, etc.) plus the nerves_fw_* metadata
#   keys -- see prebuilt/uboot-env-template.txt in the system source.
#   With matching sizes the CRC check passes for U-Boot, boardid, and
#   the Erlang `uboot_env` library, all reading from the same volume.
# - sector_size: one UBI LEB on this NAND
# - num_sectors: 1 (env fits in a single LEB)

/dev/ubi0_0	0x0	0x1F000	0x1F000	1
/dev/ubi0_1	0x0	0x1F000	0x1F000	1