Advice on serial port communication

[Joseph Olatt]

Hi,

I am trying to install OpenBSD (6.9) on a Beaglebone (Black, I presume -- it
is a kit from Vilros). I followed the instructions at:

https://ftp.openbsd.org/pub/OpenBSD/6.9/armv7/INSTALL.armv7

When I try to connect to the console via the serial port using cu, as
described in the instructions, I get lines of "C"s. This happens at only
115200 baud rate. At all other baud rates, I get nothing.

Any advice on what those "C"s mean. The serial cable I'm using is:

https://www.amazon.com/GearMo%C2%AE-3-3v-Header-like-TTL-232R-3V3/dp/B004LBXO2A/

Thank you.

[Stuart Longland]

On Mon, 24 May 2021 07:54:38 -0700
Something in the back of my mind suggests this might be the TI
bootloader complaining, about something. Maybe it can't find the
boot-loader?

[Stuart Longland]

On Tue, 25 May 2021 09:38:21 +1000

Maybe it can't find the boot-loader?

To clarify… (yes, half asleep this morning)… TI boot-loader cannot find
the OS boot-loader… not that it can't find itself.

[Joseph Olatt]

Hi Stuart,

Thank you for responding.

Please see my response/question below.

Post by Stuart Longland
On Tue, 25 May 2021 09:38:21 +1000

Maybe it can't find the boot-loader?

To clarify??? (yes, half asleep this morning)??? TI boot-loader cannot find
the OS boot-loader??? not that it can't find itself.

So, I have actually tried to power up the device without pressing the
button by the SD card reader. That also resulted in a bunch of "C"s.

Any advice on how I cat get to the U-Boot (which is what I presume you
mean by the "TI boot-loader") prompt? I am going to try to let the "C"s
run for a lot longer and see if I can reach the boot prompt.

Thank you,
joseph

Post by Stuart Longland
--
Stuart Longland (aka Redhatter, VK4MSL)
I haven't lost my mind...
...it's backed up on a tape somewhere.

[David Barrass]

Hi Joseph,

I can confirm that if I hold down the BOOT button on the BBB and power
up with no micro SD card in the slot, this is exactly what I see. Using
a known good OpenBSD SD card in the slot, it boots as expected.

HTH,

David

Post by Joseph Olatt
Hi Stuart,
Thank you for responding.
Please see my response/question below.

Post by Stuart Longland
On Tue, 25 May 2021 09:38:21 +1000

Maybe it can't find the boot-loader?

To clarify??? (yes, half asleep this morning)??? TI boot-loader cannot find
the OS boot-loader??? not that it can't find itself.

So, I have actually tried to power up the device without pressing the
button by the SD card reader. That also resulted in a bunch of "C"s.
Any advice on how I cat get to the U-Boot (which is what I presume you
mean by the "TI boot-loader") prompt? I am going to try to let the "C"s
run for a lot longer and see if I can reach the boot prompt.
Thank you,
joseph

Post by Stuart Longland
--
Stuart Longland (aka Redhatter, VK4MSL)
I haven't lost my mind...
...it's backed up on a tape somewhere.

[Joseph Olatt]

Hi David and Stuart,

Thank you to both of you for your insight and assistance.

I have OpenBSD 6.9 running on my BBB now. This is what I did:

- I created a new SD card image on an OpenBSD system (previously I was
using the Debian-based MX-Linux laptop for that.

- During the install process I tried to install on sd0 (eMMC), but I
kept getting read error on block 16. So, I installed on sd1 (SD card)

Like David mentioned, in one his previous emails, the install went
smoothly. Kudos to the OpenBSD team!

So, if you see "C"s on the console during boot up, it means that the TI
boot-loader is unable to find the OS boot loader (U-Boot).

After installation I tried to use the eMMC by doing a disklabel(8) and a
newfs(8) but kept running into the following error:

newfs: rdfs: read error on block ...

It looks like I won't be able to use the 4 GB or so of eMMC. NP.

Once again, thanks to David and Stuart for all the help.

joseph

Post by David Barrass
Hi Joseph,
I can confirm that if I hold down the BOOT button on the BBB and power
up with no micro SD card in the slot, this is exactly what I see. Using
a known good OpenBSD SD card in the slot, it boots as expected.
HTH,
David

Post by Joseph Olatt
Hi Stuart,
Thank you for responding.
Please see my response/question below.

Post by Stuart Longland
On Tue, 25 May 2021 09:38:21 +1000

Maybe it can't find the boot-loader?

To clarify??? (yes, half asleep this morning)??? TI boot-loader cannot find
the OS boot-loader??? not that it can't find itself.

So, I have actually tried to power up the device without pressing the
button by the SD card reader. That also resulted in a bunch of "C"s.
Any advice on how I cat get to the U-Boot (which is what I presume you
mean by the "TI boot-loader") prompt? I am going to try to let the "C"s
run for a lot longer and see if I can reach the boot prompt.
Thank you,
joseph

Post by Stuart Longland
--
Stuart Longland (aka Redhatter, VK4MSL)
I haven't lost my mind...
...it's backed up on a tape somewhere.

[Stuart Longland]

On Tue, 25 May 2021 08:29:52 -0700
Joseph Olatt <***@eskimo.com> wrote:

[Accidentally dropped CC… re-sending]

Post by Joseph Olatt
Any advice on how I cat get to the U-Boot (which is what I presume you
mean by the "TI boot-loader") prompt?

Nope, by "TI boot-loader", I mean "TI boot-loader", which is burned
into a ROM that exists on the die of the SoC. It has no prompt: it
just reads some GPIO pins, initialises the appropriate interface based
on the pins it sees pulled high/low then goes hunting for a boot sector.

U-Boot is the boot-loader it is failing to load in this case.

[Joseph Olatt]

Hi Stuart and David,

Thank you to you both for the amount of time and advice you have provided.

I am away from my BBB for a couple of days. As soon as I get back to it,
I will try out a few things, based on advice from both of you.

I will update after that.

Thank you.
joseph

Post by Stuart Longland
On Tue, 25 May 2021 08:29:52 -0700
[Accidentally dropped CC??? re-sending]

Post by Joseph Olatt
Any advice on how I cat get to the U-Boot (which is what I presume you
mean by the "TI boot-loader") prompt?

Nope, by "TI boot-loader", I mean "TI boot-loader", which is burned
into a ROM that exists on the die of the SoC. It has no prompt: it
just reads some GPIO pins, initialises the appropriate interface based
on the pins it sees pulled high/low then goes hunting for a boot sector.
U-Boot is the boot-loader it is failing to load in this case.
--
Stuart Longland (aka Redhatter, VK4MSL)
I haven't lost my mind...
...it's backed up on a tape somewhere.