diff --git a/hw/application_fpga/fw/tk1/preload_app.c b/hw/application_fpga/fw/tk1/preload_app.c
index 04596f2..2037a1c 100644
--- a/hw/application_fpga/fw/tk1/preload_app.c
+++ b/hw/application_fpga/fw/tk1/preload_app.c
@@ -150,6 +150,12 @@ int preload_delete(struct partition_table *part_table, uint8_t slot)
 	memset(part_table->pre_app_data[slot].auth.authentication_digest, 0x00,
 	       sizeof(part_table->pre_app_data[slot].auth.authentication_digest));
 
+	memset(part_table->pre_app_data[slot].digest, 0,
+	       sizeof(part_table->pre_app_data[slot].digest));
+
+	memset(part_table->pre_app_data[slot].signature, 0,
+	       sizeof(part_table->pre_app_data[slot].signature));
+
 	part_table_write(part_table);
 
 	/* Assumes the area is 64 KiB block aligned */