diff --git a/makefiles/boot/riotboot.mk b/makefiles/boot/riotboot.mk
index 89fdd26f7a..6edabe9f24 100644
--- a/makefiles/boot/riotboot.mk
+++ b/makefiles/boot/riotboot.mk
@@ -17,12 +17,13 @@ export SLOT0_OFFSET SLOT0_LEN SLOT1_OFFSET SLOT1_LEN
 ifeq (1, RIOT_CI_BUILD)
   APP_VER ?= 0
 else
-  APP_VER ?= $(shell date +%s)
+  EPOCH := $(shell date +%s)
+  APP_VER ?= $(EPOCH)
 endif
 
 # Final target for slot 0 with riot_hdr
-SLOT0_RIOT_BIN = $(BINDIR_APP)-slot0.riot.bin
-SLOT1_RIOT_BIN = $(BINDIR_APP)-slot1.riot.bin
+SLOT0_RIOT_BIN = $(BINDIR_APP)-slot0.$(APP_VER).riot.bin
+SLOT1_RIOT_BIN = $(BINDIR_APP)-slot1.$(APP_VER).riot.bin
 SLOT_RIOT_BINS = $(SLOT0_RIOT_BIN) $(SLOT1_RIOT_BIN)
 
 # if RIOTBOOT_SKIP_COMPILE is set to 1, "make riotboot/slot[01](-flash)"
@@ -53,7 +54,7 @@ link: $(SLOT_RIOT_ELFS)
 endif
 
 # Create binary target with RIOT header
-$(SLOT_RIOT_BINS): %.riot.bin: %.hdr %.bin
+$(SLOT_RIOT_BINS): %.$(APP_VER).riot.bin: %.hdr %.bin
 	@echo "creating $@..."
 	$(Q)cat $^ > $@