I just noticed that there are no versions of the package "u-boot" available on my SolidRun CuBox-i. However there is a version of "u-boot-imx" available which contains the actual binary code for this machine. Interestingly, I have other arm-based boxes and none of them have this problem.
See attached text capture for details. Let me know if there's anything else I can provide that will be helpful. Thanks in advance, Rick
rbthomas@half:~$ aptitude versions --disable-columns '?name(u-boot)' Package u-boot: i 2022.04+dfsg-2+b1 100 Package u-boot-exynos: i A 2023.01+dfsg-2 testing 500 Package u-boot-imx: i 2023.01+dfsg-2 testing 500 Package u-boot-menu: p 4.2.1 testing 500 Package u-boot-omap: i A 2023.01+dfsg-2 testing 500 Package u-boot-qemu: p 2023.01+dfsg-2 testing 500 Package u-boot-rockchip: p 2023.01+dfsg-2 testing 500 Package u-boot-rpi: p 2023.01+dfsg-2 testing 500 Package u-boot-stm32: p 2023.01+dfsg-2 testing 500 Package u-boot-sunxi: i A 2023.01+dfsg-2 testing 500 Package u-boot-tegra: p 2023.01+dfsg-2 testing 500 Package u-boot-tools: i 2023.01+dfsg-2 testing 500 rbthomas@half:~$ grep -v '^#' /etc/apt/sources.list deb http://deb.debian.org/debian/ bookworm main non-free contrib non-free-firmware deb http://security.debian.org/debian-security bookworm-security main contrib non-free non-free-firmware deb http://deb.debian.org/debian/ bookworm-updates main contrib non-free non-free-firmware deb http://deb.debian.org/debian/ bookworm-backports main contrib non-free non-free-firmware rbthomas@half:~$ arch armv7l rbthomas@half:~$