Re: u-boot debug, was: Re: U-boot on RPI3, sees disk but won't boot it

I found a configuration that gets the RPi3 EDK2 and FreeBSD
combination to have the serial console working. You can try
booting and operating via the RPi3 EDK2 UEFI materials.

However, microsd cards should still not be mounted/used from
a FreeBSD that has been booted via RPi3 EDK2. Bluetooth is
disabled as part of getting a working serial console.

I ended up with a RPi3 EDK2 microsd card for use in booting
that has:

# mount -onoatime -tmsdosfs /dev/da3s1 /mnt
# find /mnt -print
/mnt
/mnt/RPI_EFI.fd
/mnt/bootcode.bin
/mnt/config.txt
/mnt/fixup.dat
/mnt/start.elf
/mnt/Readme.md
/mnt/bcm2710-rpi-3-b-plus.dtb
/mnt/bcm2710-rpi-3-b.dtb
/mnt/bcm2710-rpi-cm3.dtb
/mnt/firmware
/mnt/firmware/Readme.txt
/mnt/firmware/brcmfmac43455-sdio.txt
/mnt/firmware/brcmfmac43455-sdio.bin
/mnt/firmware/brcmfmac43455-sdio.clm_blob
/mnt/firmware/LICENCE_bin+clm_blob.txt
/mnt/firmware/brcmfmac43430-sdio.clm_blob
/mnt/firmware/brcmfmac43430-sdio.txt
/mnt/firmware/brcmfmac43430-sdio.bin
/mnt/firmware/LICENSE_txt.txt
/mnt/overlays
/mnt/overlays/disable-bt.dtbo

All but the 2 "overlays" lines are based on the content of:

https://github.com/pftf/RPi3/releases/download/v1.37/RPi3_UEFI_Firmware_v1.37.zip

disable-bt.dtbo is a copy of one from a RPi* firmware
used for booting FreeBSD on RPi*s. It is not in the .zip
file.

I adjusted config.txt to indicate to use the disable-bt.dtbo :

# more /mnt/config.txt
arm_64bit=1
disable_commandline_tags=2
disable_overscan=1
enable_uart=1
uart_2ndstage=1
armstub=RPI_EFI.fd
device_tree_address=0x1f0000
device_tree_end=0x200000
#
# Local addition(s):
dtoverlay=disable-bt

(The file has a carriage returns at the end of each
line. Some editors show such characters as ^M .
The characters could be deleted if desired.)

I'll note that the firmware/* content is likely of
no use for FreeBSD at this point but I did not
remove it. It should be okay to not have it present.

I'll note that the output from "uart_2ndstage=1" does
not actually display during the boot sequence. (Sent
to the wrong internal UART, as if dtoverlay=disable-bt
had not been used, from what I understand.)

Using that microsd card in the RPi3B should try to
boot. The EFI prompt will timeout and continue to the
next stage (so far as it is successful, anyway). If
it all works, it will get to the "login: " prompt.
I'm not familiar with what the error reporting would
be like if it also has troubles with your equipment.

You hit the return key to explicitly continue at the
EFI prompt. The Escape key can be used instead to get
into the menu system for controlling the UEFI
settings.

If it gets far enough, the UEFI will try to find the
EFI/BOOT/* on your USB media's msdosfs. If found, it
will then load the FreeBSD loader and  then start it
--and things would then be back in familiar territory.


The above actually boots via a default setting that likely
should be replaced. The related menu/field nesting is:

Device Manager
    Raspberry Pi Configuration
        Advanced Configuration
            System Table Selection <ACPI + Devicetree>

Picking just Devicetree instead, then saving, and then
exiting the nested menus via a sequence of Escape key
presses, until back to the initial display, one can
then select Reset and it will start over based on the
new setting. The save actually updates an area in the
RPI_EFI.fd file.

(The issue is that the ACPI information is odd:
Microsoft specific, not standard. So if the ACPI
information is used things are possibly not
complete/correct.)

===
Mark Millard
marklmi at yahoo.com