I bought Samsung Sonic The Hedgehog (128GB, $23.69).  180MB/130MB written on the package.  I was considering Lexar Professional SILVER PLUS (128GB, $24.99).  205MB/150MB on Lexar website.  Let's see what else comes up on Black Friday sales.

I was successful in making the board into a keyboard, but with older kernels.  Older factory images (based on Debian 8.7, 9.9, 10.13) have the relevant drivers as modules.  So, I was able to blacklist unnecessary or conflicting modules, and load only the modules I need.  Also, the program that sends out key presses is Python2 script, and older images have Python2 package.

Newer factory images (based on Debian 11.7, 12.12, 13.1) have USB Gadget drivers built into the kernel.  So, I couldn't create a new device, because it's already being "used".  The module I want is "usb_f_hid", and I found that it conflicts with "usb_f_acm".  Also, the newer images don't have Python2 installed and it's not available in their repositories.

• Rewrite Python2 scripts into Bash shell scripts.  --Done.  Shell scripts are cleaner.

• Compile ARM kernel with all USB Gadget drivers as modules.  --Done.  It took 24 hours to compile kernel on the BeagleBone Black board with that new speedy Samsung card.

• Figure out how to build initrd.img.

• Figure out how bootloader picks up the kernel.

• Write up documentation in GitHub.

• Learn more about USB Gadget device configuration.

On Sun, Nov 02, 2025 at 03:08:24AM -0500, William Park via Talk wrote:

I'm trying to make BeagleBone Black
<https://www.beagleboard.org/boards/beaglebone-black> into a programmable
keyboard (and mouse, hopefully).  It has one "USB device" port (mini-USB)
and one more common "USB host" port (USB-A).  It boots off microSD or eMMC. 
One frustration is slow speed of my SD cards.  I have lots of them, 8-16GB
and 5MB/s. Too slow to flash images, and too slow to run on it.

So, I've been shopping around for a *fast* microSD card.  What I don't
understand is,
    - some U1 cards are faster than U3 cards.  This means, I can't just
search for "U3" cards.

- Do you know why U3 cards are slower than U1 cards?
- Any brand recommendation?
    - Canada Computer has lots of "Teamgroup".  Are they good?  They are new
(to me).
    - Of course, can't go wrong with Samsung.  But, not at $20 range.
    - no Kingston.  All the dead cards were from Kingston.

As far as I know, the beagleboard black does NOT support UHS at all,
so you actually care what speed the card supports when not in UHS mode.
UHS mode requires switching the IO voltage to 1.8V, which the BeagleY-AI
supports, but not the older beable boards it seems.  So probably something
meant to be used as a Class 10 (and maybe UHS-I) is likely to operate
faster when running at 3.3V than a card designed for 1.8V for optimal
performance.

No matter what the 4bit (if supported by the card, otherwise 1bit)
microSD interface will never match the speed of the 8bit eMMC interface
on the BBB.