Date: Wed, 27 Oct 2021 17:02:27 -0700 From: Mark Millard via freebsd-arm <freebsd-arm@freebsd.org> To: bob prohaska <fbsd@www.zefox.net> Cc: Free BSD <freebsd-arm@freebsd.org>, freebsd-ports@freebsd.org Subject: Re: Troubles booting Pi2 from USB using bootcode.bin method Message-ID: <02806205-6685-41FD-B2D1-415C82FBCF92@yahoo.com> In-Reply-To: <41C0A656-D898-4381-BB81-034D54CA04A0@yahoo.com> References: <20211025034332.GA8398@www.zefox.net> <20211027162852.GA16010@www.zefox.net> <F54AB76B-83AE-40BD-B035-F35C7B898357@yahoo.com> <41C0A656-D898-4381-BB81-034D54CA04A0@yahoo.com>
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On 2021-Oct-27, at 15:37, Mark Millard <marklmi@yahoo.com> wrote: > On 2021-Oct-27, at 10:39, Mark Millard <marklmi@yahoo.com> wrote: >=20 >> On 2021-Oct-27, at 09:28, bob prohaska <fbsd@www.zefox.net> wrote: >>=20 >>> On Sun, Oct 24, 2021 at 08:43:32PM -0700, bob prohaska wrote: >>>> I've got an early Pi2B (not plus) that has been booting reliably >>>> from a USB2 disk connected via a USB3 hub using just bootcode.bin >>>> and timeout on the DOS partition of the microSD card. >>>>=20 >>> It turns out the USB3 disk boots normally _provided_ the old >>> USB2 disk remains connected. I didn't try that initially both >>> because I didn't need both disks and because the boot order=20 >>> couldn't be obviously controlled.=20 >>>=20 >>> It turns out the new disk is discovered first and boots as=20 >>> desired, so the system is busy building an up-to-date world >>> and kernel. There's room for a ports tree on this disk. >>>=20 >>> Does the ports version of u-boot include support for the >>> bootcode.bin-only mode of USB booting? >>=20 >> Before U-Boot is involved there are other files involved >> such as a start* file from the USB device. With appropriate >> config.txt content, and possibly other settings, the boot >> is likely rather explicit about its early activity. (But I >> do not currently have access to a RPi2B v1.1 or earlier to >> test the details on. In fact, the accessible only RPi*'s >> are RPi4B 8 GiByte ones.) >>=20 >> (I wondered if you meant RPi3B: To my knowledge there is >> no such thing as a RPi2B+ so the "plus" reference suggests >> an early RPi3B might have been what was involved.) >>=20 >>> Right now I'm using >>> the version of bootcode.bin offered at=20 >>> = https://www.raspberrypi.com/documentation/computers/raspberry-pi.html#spec= ial-bootcode-bin-only-boot-mode >>>=20 >>> Without having the USB2 disk connected the serial console hangs >>> with what looks like "cb" as the only output. It's unclear if >>> u-boot is starting at all. The red and green LEDs remain lit, >>> seemingly indefinitely.=20 >>>=20 >>=20 >=20 > Your specific path may be different, but what does a command > analogous to the below show for you for the problematical > context? >=20 > # strings /boot/efi/start.elf | grep "VC_BUILD_" > VC_BUILD_ID_USER: dom > VC_BUILD_ID_TIME: 12:12:09 > VC_BUILD_ID_VARIANT: start > VC_BUILD_ID_TIME: Feb 25 2021 > VC_BUILD_ID_BRANCH: bcm2711_2 > VC_BUILD_ID_HOSTNAME: buildbot > VC_BUILD_ID_PLATFORM: raspberrypi_linux > VC_BUILD_ID_VERSION: 564e5f9b852b23a330b1764bcf0b2d022a20afd0 (clean) >=20 > I'll note that there is: >=20 > QUOTE > bootcode.bin UART Enable >=20 > NOTE > For boards pre-Raspberry Pi 4, Model B. > For information on enabling the UART on the Pi4 bootloader, please see = this page. >=20 > It is possible to enable an early stage UART to debug booting issues = (useful with the above bootcode.bin only boot mode). To do this, make = sure you=E2=80=99ve got a recent version of the firmware (including = bootcode.bin). To check if UART is supported in your current firmware: >=20 > strings bootcode.bin | grep BOOT_UART >=20 > To enable UART from bootcode.bin use: >=20 > sed -i -e "s/BOOT_UART=3D0/BOOT_UART=3D1/" bootcode.bin >=20 > Next, connect a suitable USB serial cable to your host computer (a = Raspberry Pi will work, although I find the easiest path is to use a USB = serial cable since it=E2=80=99ll work out the box without any pesky = config.txt settings). Use the standard pins 6, 8 and 10 (GND, GPIO14, = GPIO15) on a Pi or CM board. >=20 > Then use screen on linux or a Mac or putty on windows to connect to = the serial. >=20 > Setup your serial to receive at 115200-8-N-1, and then boot your Pi / = Compute module. You should get an immediate serial output from the = device as bootcode.bin runs. > END QUOTE >=20 > That text is from: >=20 > https://www.raspberrypi.com/documentation/computers/raspberry-pi.html >=20 For more debug information on the serial console, but somewhat later in the sequence than the output for BOOT_UART=3D1, config.txt can contain: enable_uart=3D1 uart_2ndstage=3D1 dtdebug=3D1 The debug output is before U-Boot starts but likely does indicate the = loading of u-boot.bin (as the kernel) and when in the sequence it is about to start code in u-boot.bin . (It may also report more at shutdown.) =3D=3D=3D Mark Millard marklmi at yahoo.com ( dsl-only.net went away in early 2018-Mar)
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