If you use 'dboot linux mmc' the U-Boot environment variable 'fdt_file' is used to select which device tree blob use during boot. By default a DTB with the minimum set of interfaces is used, to ensure compatibility. That is why you do not have wireless interface if you boot this way. (You can solve this by setting fdt_file to the DTB you want to use).
Anyways, that is not the correct way to boot. Once U-Boot has been flashed and the environment reset, the correct way to boot is to run 'boot'. Some features depends on this (for example device tree selection, and bootscript authentication if using TrustFence).