diff --git a/Makefile b/Makefile
index 3ddb6b6df..b2cd3714a 100644
--- a/Makefile
+++ b/Makefile
@@ -179,11 +179,16 @@ ifneq ($(wildcard $(TARGET)/images/firmware.bin),)
 # squashfs is: at the block right after the uImage is the split layout, at the
 # slot boundary fixed slots. A fixed-slot uImage ending in the slot's last block
 # would be both.
+#
+# The fixed-slot package is the extra: a build whose uImage or rootfs has
+# outgrown its slot ships the split package alone rather than failing, and
+# says so. Cameras on fixed slots then upgrade to the split layout, which
+# sysupgrade and defib install from the -split package.
 ifeq ($(BR2_OPENIPC_NOR_FIXED_PACKAGE),y)
 ifeq ($(BR2_OPENIPC_FLASH_SIZE),"8")
-	@$(call PREPARE_REPACK,uImage,1983,rootfs.squashfs,5120,nor)
+	@$(if $(call FIXED_SLOTS_FIT,5120),$(call PREPARE_REPACK,uImage,1983,rootfs.squashfs,5120,nor),$(call FIXED_SLOTS_SKIP,5120))
 else
-	@$(call PREPARE_REPACK,uImage,1983,rootfs.squashfs,8192,nor)
+	@$(if $(call FIXED_SLOTS_FIT,8192),$(call PREPARE_REPACK,uImage,1983,rootfs.squashfs,8192,nor),$(call FIXED_SLOTS_SKIP,8192))
 endif
 endif
 	@$(call CHECK_SIZE,firmware.bin,$(shell expr $(subst ",,$(BR2_OPENIPC_FLASH_SIZE)) \* 1024 - $$(( $(or $(BR2_OPENIPC_NOR_FIRMWARE_OFFSET),0x50000) / 1024 )) - 256))
@@ -368,6 +373,23 @@ define REPACK_FIRMWARE
 	rm -f $(TARGET)/images/*.md5sum
 endef
 
+# Whether uImage and rootfs.squashfs fit the fixed slots beside a split image:
+# the uImage under 1984K (see the repack target), the rootfs within $(1) KB,
+# both counted in whole KB as CHECK_SIZE counts them. "y" or empty.
+FIXED_SLOTS_FIT = $(shell k=$$(( $$(stat -c %s $(TARGET)/images/uImage 2>/dev/null || echo 0) / 1024 )); \
+	r=$$(( $$(stat -c %s $(TARGET)/images/rootfs.squashfs 2>/dev/null || echo 0) / 1024 )); \
+	[ $$k -gt 0 ] && [ $$k -le 1983 ] && [ $$r -gt 0 ] && [ $$r -le $(1) ] && echo y)
+
+define FIXED_SLOTS_SKIP
+	k=$$(( $$(stat -c %s $(TARGET)/images/uImage) / 1024 )); \
+	r=$$(( $$(stat -c %s $(TARGET)/images/rootfs.squashfs) / 1024 )); \
+	over=; \
+	[ $$k -le 1983 ] || over="uImage $${k}KB/1983KB"; \
+	[ $$r -le $(1) ] || over="$${over:+$$over, }rootfs.squashfs $${r}KB/$(1)KB"; \
+	echo "::warning::$(BR2_OPENIPC_SOC_MODEL) $(BR2_OPENIPC_VARIANT): $$over outgrew the fixed slot;" \
+		"shipping the split package only"
+endef
+
 # The split NOR package: firmware.bin alone, under its own name so a sysupgrade
 # that predates the layout never sees it. Copies, as REPACK_NAND_FIT does.
 define REPACK_NOR_SPLIT