Which one of these http://beagleboard.org/latest-images do you put on a
SD-Card or USB flash memory stick?
The BBAI is a 5729 SoC. I wouldn't use any of the images from that page
-- they are nearly a year old and you would need a large uSD or eMMC
freespace to run an "apt update/apt upgrade" sequence.
I'd suggest visiting https://rcn-ee.net/rootfs/bb.org/testing/ and
checking for a more recent build that includes the updates of the last
year. Maybe not the most recent build (these /are/ labeled "testing, after
all) but not too old either. (Note that 2021-02-15 has Debian 10.8, vs the
10.3 of the "latest images" page). Decide if you want a graphical desktop
(images with LXQT) or Internet of Things (images with iot), TI Deep
Learning (images with tidl) [Note that these are not mutually exclusive:
LXQT & TIDL, IOT & TIDL, LXQT only, IOT only)]
Which updates the on board memory?
Updating the eMMC is performed by loading the appropriate "Flasher"
image onto an uSD card, and booting with that card inserted.
Alternatively, non-flasher images can be turned into flasher images by
editing the /boot/uEnv.txt file. Typically the last line of that file has a
commented line; removing the # from the line enables the flashing mode.
Note that if you boot with a flasher image, it WILL rewrite the eMMC --
every time. You would have to mount the uSD after a boot from the eMMC to
recomment the line in uEnv.txt.