can we have HS200 be the default but an armbian-config option to enable HS400 via an overlay [with appropriate warnings/documentation]? fwiw I have a NanoPC-T6 with current/mainline kernel [running my HomeAssistant, so I'm loathe to mess with it] that I had to abandon using the eMMC due to IO errors. It's in the official case so can't do much inspection either.

ARM CPU running Linux 2GB RAM NPU for AI (maybe as little as CV) ARM MPU running Sketch (Arduino) https://store-usa.arduino.cc/products/uno-q Closed source

PR for these changes: https://github.com/armbian/build/pull/8734

@JohnTheCoolingFan what image are you using? I can reproduce the issue consistently with Armbian_25.8.1_Bigtreetech-cb1_bookworm_current_6.12.35_minimal.img . This is the Minimal / IOT image one can grab from https://www.armbian.com/bigtreetech-cb1/ . Interestingly enough, the Minimal / IOT image does not use NetworkManager, it's configured with systemd-networkd backend (or "renderer" as they call it) for netplan. Perhaps this is the key difference: I saw a comment on a topic below stating that MainsailOS has added CB1 Trixie image which is forced to NetworkManager and it's claimed to be stable.

That was just a simple one-liner (fdtoverlay -i rk3588-nanopc-t6.dtb -o rk3588-nanopc-t6.dtb rk3588-nanopc-t6-emmc.dtbo). In order to carry out the test in my environment, the typing task was a little more complex: It apparently depends on how the overlay was applied, because fundamentally it should also work when applied dynamically. However, the static application of an overlay has the disadvantage that in the case of an incompatibility, one is only confronted with an error message and does not experience a system that fails to start. It is not very difficult to get it out. It is held only by the slight adhesive strength of the thermal pad between the SoC and the casing when the bottom plate is removed. A cautious light steady pull releases it. The only difficulty is in gripping the board to make apply this pull. I screwed a bolt into one of the mounting PCB nuts and used it as a handle. With such a socket in one of the SMA antenna connection ports, the UART connection can be permanently routed to the outside without modifying the casing. I use it to route the fan connector outside. Without the possibility of providing meaningful serial console logs, you will probably be left on your own with it.