NAME
	/harness/rom.bin

DESCRIPTION
	Read access to the RP2040 CPU's ROM.  This contains code that
	initializes the chip to load the main firmware from the
	external flash chip, provides a failsafe USB-programmable
	mode, and provides a few functions that the main firmware can
	call to.

BUGS
	This ROM is programmed into the chip at the factory; revising
	it means issuing a new revison of the RP2040 CPU.  So while
	the source code to the ROM is freely available to be used,
	studied, and shared; one cannot install modified versions onto
	the CPU.

HISTORY
	- RP2040 B0 : chips manufactured before September 2020 or so
	- RP2040 B1 : chips manufactured after September 2020 or so
	- Released to the public January 2021; chance whether you get
	  a B0 or a B1 chip.
	- RP2040 B2 : released September 2021

	Printed on the physical CPU is a label that indicates which
	revision it is.  For example:

		RP2-B2  21/24

	indicates that it is the "B2" revision (and was manufactured
	the 21st week (late May) of 2024).

SEE ALSO
	- /harness/cpuinfo.txt can report which CPU version you have.

	- The source code to each ROM revision is published at
	  https://github.com/raspberrypi/pico-bootrom-rp2040

AUTHOR
	Copyright (C) 2025  Luke T. Shumaker <lukeshu@lukeshu.com>
	SPDX-License-Identifier: AGPL-3.0-or-later