Apologies if i misunderstood, are you attempting to install armbian on eMMC or on your m.2 SSD?
Well the first preference is SD card / USB device, and the second preference is eMMC.
Regarding installing on eMMC you can follow these steps:
- Remove all the devices which might power the device
- Not officially mentioned but just to be safe remove any storage devices
- Connect the USB to TYPEC port on your Banana Pi M7 and the other end to your PC
- Make sure drivers are installed for your device (I am using windows for this so i only know how to do so via windows)
- Use RKDevTool v2.96 (In the official docs they provided an older version, just use 2.96 since i've personally tested it and it works)
- Hold the reset button (if flashing for first time) Or Markrom button, and only THEN insert the DCIN (make sure it has atleast 35W of power)
- If your drivers were installed, it should successfully show your device in Maskrom mode in your RKDevtool 2.96
- Do this:
- Make sure to check Write by Address, it's important
- Another thing, the image you select here should be .img, and not .img.xz (extract it first if its .xz)
- It should install armbian on your device.
Here's my sources:
Getting Started BPI-M7 | BananaPi Docs (Install Image to eMMC 2 section)