# LithosAnanke native (non-UEFI) boot config for Raspberry Pi 5 (BCM2712).
# FABRIC-3.md §IV.3 item 6 -- see that section's own doc comment for the
# research trail behind each line (confirmed against raspberrypi.com's
# current config.txt reference and a real, working Pi 5 bare-metal
# project's own checked-in config.txt, not assumed from general Pi
# knowledge).

# Load our own kernel image directly -- no UEFI, no Linux. kernel_2712.img
# is the real filename Pi 5/500/CM5 firmware looks for first (its own
# 16K-page-size build); naming our own image this exactly, rather than
# falling back to kernel8.img, removes any ambiguity about which file the
# firmware picks up.
kernel=kernel_2712.img

# Disable the firmware's Linux-compatible-image sanity check. Without
# this, official docs describe it as checking for "a compatible Device
# Tree file before attempting to boot" and warn that "older non-compatible
# kernels would be loaded and then hang" -- documented specifically as the
# bare-metal-development escape hatch. One real working Pi 5 bare-metal
# project's own config.txt does NOT set this and still boots, so it may
# not be strictly required for every non-Linux image; kept here anyway
# since the official doc names this exact use case and there is no
# hardware in hand yet to verify which behavior is actually gated.
os_check=0

# Pin the exact devicetree explicitly rather than relying on the
# firmware's own board-revision auto-selection (which would also resolve
# to this file on real Pi 5 hardware, per general config.txt convention --
# explicit is certain, not just probably-correct).
device_tree=bcm2712-rpi-5-b.dtb

# Enable the dedicated debug UART (Pi 5's own JST connector, not the GPIO
# 14/15 header pins). Not because serial capture hardware is set up for
# this bring-up (that decision is HDMI-only, FABRIC-3.md §IV) -- this is
# a firmware-side switch that costs nothing when nothing is listening, and
# it is the only diagnostic channel that survives a framebuffer failure.
# rpi5_uart_base() (rpi5_dtb.c) already exists and is currently uncalled;
# this is the hook a UART-based fallback console would use if the mailbox
# framebuffer driver's two documented unverified details turn out wrong on
# real hardware.
enable_uart=1

# Deliberately NOT set, researched but not included this pass:
#   dtoverlay=uart0   -- GPIO 14/15 header UART; needs a USB-serial
#                        adapter this bring-up doesn't have (HDMI-only
#                        decision). enable_uart=1 above covers the JST
#                        debug UART instead, which needs no extra cable.
#   dtparam=pciex1    -- one real Pi 5 bare-metal project's own config.txt
#                        comments this as "Required for RP1 access", which
#                        would be surprising (RP1 is always-on in stock Pi
#                        5 boots) and is community-reported, not confirmed
#                        against official docs. Not needed for this boot
#                        (no RP1 access yet -- FABRIC-3.md §IV.3 item 5 is
#                        still re-scoped, not implemented). Revisit if that
#                        item's own real Broadcom-indirect PCIe work needs
#                        it.
#   arm_64bit=1       -- researched and dropped: official docs state
#                        "Models that only support a 64-bit kernel ignore
#                        this flag" -- inert on Pi 5, not wrong to include,
#                        just meaningless. The original item 6 wording
#                        named this; corrected here rather than carried
#                        forward.