diff --git a/package/base-files/files/lib/upgrade/nand.sh b/package/base-files/files/lib/upgrade/nand.sh
index e868ba9537..9fa3cd2ddd 100644
--- a/package/base-files/files/lib/upgrade/nand.sh
+++ b/package/base-files/files/lib/upgrade/nand.sh
@@ -387,9 +387,11 @@ nand_verify_tar_file() {
 
 nand_do_flash_file() {
 	local file="$1"
+	local cmd="$2"
+	local file_type
 
-	local cmd="$(identify_if_gzip "$file")cat"
-	local file_type="$(identify "$file" "$cmd" "")"
+	[ -z "$cmd" ] && cmd="$(identify_if_gzip "$file")cat"
+	file_type="$(identify "$file" "$cmd" "")"
 
 	[ ! "$(find_mtd_index "$CI_UBIPART")" ] && CI_UBIPART=rootfs
 
@@ -423,17 +425,22 @@ nand_do_restore_config() {
 # Supported firmware containers:
 # 1. Raw file
 # 2. Gzip
+# 3. Custom (requires passing extracting command)
 #
 # Supported data formats:
 # 1. Tar with kernel/rootfs
 # 2. UBI image (built using "ubinized")
 # 3. UBIFS image (to update UBI volume with)
 # 4. FIT image (to update UBI volume with)
+#
+# $(1): firmware file path
+# $(2): (optional) pipe command to extract firmware
 nand_do_upgrade() {
 	local file="$1"
+	local cmd="$2"
 
 	sync
-	nand_do_flash_file "$file" && nand_do_upgrade_success
+	nand_do_flash_file "$file" "$cmd" && nand_do_upgrade_success
 	nand_do_upgrade_failed
 }