diff --git a/target/linux/bcm53xx/base-files/lib/upgrade/platform.sh b/target/linux/bcm53xx/base-files/lib/upgrade/platform.sh
index e53c2513d2..88629549dc 100644
--- a/target/linux/bcm53xx/base-files/lib/upgrade/platform.sh
+++ b/target/linux/bcm53xx/base-files/lib/upgrade/platform.sh
@@ -152,12 +152,17 @@ platform_pre_upgrade() {
 		echo "Unable to find \"linux\" partition size"
 		exit 1
 	}
-	linux_length=$((0x$linux_length + 28))
+	linux_length=$((0x$linux_length))
+	local kernel_length=$(wc -c $dir/kernel | cut -d ' ' -f 1)
+	[ $kernel_length -gt $linux_length ] && {
+		echo "New kernel doesn't fit \"linux\" partition."
+		return
+	}
 	rm -f /tmp/null.bin
 	rm -f /tmp/kernel.trx
 	touch /tmp/null.bin
 	otrx create /tmp/kernel.trx \
-		-f $dir/kernel -b $linux_length \
+		-f $dir/kernel -b $(($linux_length + 28)) \
 		-f /tmp/null.bin
 
 	# Prepare UBI image (drop unwanted extra blocks)