Change all '$(...)' variable references into '${...}'
which makes the environment compatible with the hush shell.
WARNING: Support for the old '$(...)' syntax will be
discontinued in a later version.
diff --git a/board/esd/hh405/hh405.c b/board/esd/hh405/hh405.c
index 5c0d070..3158803 100644
--- a/board/esd/hh405/hh405.c
+++ b/board/esd/hh405/hh405.c
@@ -263,7 +263,7 @@
 au_image_t au_image[] = {
 	{"hh405/preinst.img", 0, -1, AU_SCRIPT},
 	{"hh405/u-boot.img", 0xfff80000, 0x00080000, AU_FIRMWARE},
-	{"hh405/pImage_$(bd_type)", 0x00000000, 0x00100000, AU_NAND},
+	{"hh405/pImage_${bd_type}", 0x00000000, 0x00100000, AU_NAND},
 	{"hh405/pImage.initrd", 0x00100000, 0x00200000, AU_NAND},
 	{"hh405/yaffsmt2.img", 0x00300000, 0x01c00000, AU_NAND},
 	{"hh405/postinst.img", 0, 0, AU_SCRIPT},