tools/autobuild: Provide .uf2 images for esp32 builds when available.

Signed-off-by: Damien George <damien@micropython.org>

tools/autobuild/build-boards.sh

@@ -30,8 +30,8 @@ function build_board {
             dest=$dest_dir/$descr$fw_tag.$ext
             if [ -r $build_dir/firmware.$ext ]; then
                 mv $build_dir/firmware.$ext $dest
-            else
-                # esp32 has micropython.elf and micropython.map
+            elif [ -r $build_dir/micropython.$ext ]; then
+                # esp32 has micropython.elf, etc
                 mv $build_dir/micropython.$ext $dest
             fi
         done
@@ -93,7 +93,7 @@ function build_esp32_boards {
         else
             if [ $mcu != esp32 ]; then
                 # build esp32-s2/s3/c3 based boards with IDF v4.4+
-                build_board $board_json $fw_tag $dest_dir bin elf map
+                build_board $board_json $fw_tag $dest_dir bin elf map uf2
             fi
         fi
     done