diff -Nru u-boot-2021.01+dfsg/debian/changelog u-boot-2021.01+dfsg/debian/changelog
--- u-boot-2021.01+dfsg/debian/changelog	2021-06-02 16:52:03.000000000 +0100
+++ u-boot-2021.01+dfsg/debian/changelog	2021-07-15 13:01:50.000000000 +0100
@@ -1,3 +1,10 @@
+u-boot (2021.01+dfsg-4ubuntu3) impish; urgency=medium
+
+  * Implement u-boot-sifive.postinst to upgrade u-boot in loader1/loader2
+    partitions upon package upgrades. LP: #1936370
+
+ -- Dimitri John Ledkov <dimitri.ledkov@canonical.com>  Thu, 15 Jul 2021 13:01:50 +0100
+
 u-boot (2021.01+dfsg-4ubuntu2) impish; urgency=medium
 
   * Revert '* debian/rules: Ensure debugging symbols are enabled.' as it
diff -Nru u-boot-2021.01+dfsg/debian/u-boot-sifive.postinst u-boot-2021.01+dfsg/debian/u-boot-sifive.postinst
--- u-boot-2021.01+dfsg/debian/u-boot-sifive.postinst	1970-01-01 01:00:00.000000000 +0100
+++ u-boot-2021.01+dfsg/debian/u-boot-sifive.postinst	2021-07-15 12:55:16.000000000 +0100
@@ -0,0 +1,23 @@
+#!/bin/sh
+
+##DEBHELPER##
+
+set -e
+
+case "$1" in
+    configure)
+        target=""
+        if grep -q '^SiFive HiFive Unleashed A00$' /sys/firmware/devicetree/base/model; then
+            target="sifive_fu540"
+        fi
+        if grep -q '^SiFive HiFive Unmatched A00$' /sys/firmware/devicetree/base/model; then
+            target="sifive_hifive_unmatched_fu740"
+        fi
+        if [ -n "$target" ] && [ -e /dev/disk/by-partlabel/loader1 ] && [ -e /dev/disk/by-partlabel/loader2 ]; then
+            dd if=/usr/lib/u-boot/$target/u-boot-spl.bin of=/dev/disk/by-partlabel/loader1
+            dd if=/usr/lib/u-boot/$target/u-boot.itb of=/dev/disk/by-partlabel/loader2
+        fi
+        ;;
+esac
+
+exit 0