I think the user will expect their device to boot on its own without having to manually input commands at the EFI boot prompt. I have this applied locally, but I'm not sure it's ideal, so would like to discuss with folks more familiar with wic and/or EFI, as I'm not an expert at either:

diff --git i/scripts/lib/wic/plugins/source/bootimg-efi.py w/scripts/lib/wic/plugins/source/bootimg-efi.py
index a4734c9..960c672 100644
--- i/scripts/lib/wic/plugins/source/bootimg-efi.py
+++ w/scripts/lib/wic/plugins/source/bootimg-efi.py
@@ -24,6 +24,7 @@
 # Tom Zanussi <tom.zanussi (at] linux.intel.com>
 #
 
+import glob
 import os
 import shutil
 
@@ -197,6 +198,12 @@ class BootimgEFIPlugin(SourcePlugin):
         except KeyError:
             msger.error("bootimg-efi requires a loader, none specified")
 
+        # Auto startup for /EFI/BOOT/boot*.efi
+        bootfiles = glob.glob('%s/EFI/BOOT/boot*.efi' % hdddir)
+        if bootfiles and len(bootfiles) == 1:
+            with open('%s/startup.nsh' % hdddir, 'w') as f:
+                f.write('fs0:\\EFI\\BOOT\\%s\n' % os.path.basename(bootfiles[0]))
+
         du_cmd = "du -bks %s" % hdddir
         out = exec_cmd(du_cmd)
         blocks = int(out.split()[0])