Hello, I realise this is quite an old bug, but it would still be of interest to me to get this enabled. The -@ option will increase the size of the compiled device tree blobs somewhat, but on the flipside, u-boot-menu's device tree overlay functionality will actually be useful.
In my case, I'm interested in this for PINE64's Quartz64 lineup of ARM devices. Since these are development boards that expose non-enumerating protocols like I2C and SPI, the use of device tree overlays is pretty much required to add additional modules to the board. Kind regards, Nicolas Frattaroli