diff --git a/0001-Revert-Fix-checksum-failure-with-small-isos.patch b/0001-Revert-Fix-checksum-failure-with-small-isos.patch
new file mode 100644
index 0000000..505d006
--- /dev/null
+++ b/0001-Revert-Fix-checksum-failure-with-small-isos.patch
@@ -0,0 +1,67 @@
+From 14e4bac91c6aba61fe56c8d9a59cf7f07dbb99ab Mon Sep 17 00:00:00 2001
+From: "Brian C. Lane" <bcl@redhat.com>
+Date: Mon, 29 Apr 2024 11:35:14 -0700
+Subject: [PATCH] Revert "Fix checksum failure with small isos"
+
+This reverts commit e313746011768ed69587fcda88ff65951af90ccc.
+
+This patch causes short checksums (57 characters instead of 60) to be
+written, resulting in a checksum that doesn't cover the whole iso and
+which fails when checked with previous checkisomd5sum versions.
+
+The incorrect checksums are shown with a ';FR' at the end instead of the
+last 3 digits.
+---
+ libcheckisomd5.c   | 4 ++--
+ libimplantisomd5.c | 6 +++---
+ 2 files changed, 5 insertions(+), 5 deletions(-)
+
+diff --git a/libcheckisomd5.c b/libcheckisomd5.c
+index adcd938..2d350bc 100644
+--- a/libcheckisomd5.c
++++ b/libcheckisomd5.c
+@@ -66,7 +66,7 @@ static enum isomd5sum_status checkmd5sum(int isofd, checkCallback cb, void *cbda
+     size_t previous_fragment = 0UL;
+     off_t offset = 0LL;
+     while (offset < total_size) {
+-        const size_t nbyte = MIN((size_t)(total_size - offset), MIN(fragment_size, buffer_size));
++        const size_t nbyte = MIN((size_t)(total_size - offset), buffer_size);
+ 
+         ssize_t nread = read(isofd, buffer, nbyte);
+         if (nread <= 0L)
+@@ -89,7 +89,7 @@ static enum isomd5sum_status checkmd5sum(int isofd, checkCallback cb, void *cbda
+             const size_t current_fragment = offset / fragment_size;
+             const size_t fragmentsize = FRAGMENT_SUM_SIZE / info->fragmentcount;
+             /* If we're onto the next fragment, calculate the previous sum and check. */
+-            if (current_fragment != previous_fragment && current_fragment < info->fragmentcount) {
++            if (current_fragment != previous_fragment) {
+                 if (!validate_fragment(&hashctx, current_fragment, fragmentsize,
+                                        info->fragmentsums, NULL)) {
+                     /* Exit immediately if current fragment sum is incorrect */
+diff --git a/libimplantisomd5.c b/libimplantisomd5.c
+index d5f32fc..217c896 100644
+--- a/libimplantisomd5.c
++++ b/libimplantisomd5.c
+@@ -109,8 +109,8 @@ int implantISOFD(int isofd, int supported, int forceit, int quiet, char **errstr
+     const off_t fragment_size = total_size / (FRAGMENT_COUNT + 1);
+     size_t previous_fragment = 0UL;
+     off_t offset = 0LL;
+-    while (offset < total_size && previous_fragment < FRAGMENT_COUNT) {
+-        const size_t nbyte = MIN((size_t)(total_size - offset), MIN(fragment_size, buffer_size));
++    while (offset < total_size) {
++        const size_t nbyte = MIN((size_t)(total_size - offset), buffer_size);
+         ssize_t nread = read(isofd, buffer, nbyte);
+         if (nread <= 0L)
+             break;
+@@ -119,7 +119,7 @@ int implantISOFD(int isofd, int supported, int forceit, int quiet, char **errstr
+         const size_t current_fragment = offset / fragment_size;
+         const size_t fragmentsize = FRAGMENT_SUM_SIZE / FRAGMENT_COUNT;
+         /* If we're onto the next fragment, calculate the previous sum and check. */
+-        if (current_fragment != previous_fragment && current_fragment < FRAGMENT_COUNT) {
++        if (current_fragment != previous_fragment) {
+             validate_fragment(&hashctx, current_fragment, fragmentsize, NULL, fragmentsums);
+             previous_fragment = current_fragment;
+         }
+-- 
+2.44.0
+
diff --git a/isomd5sum.spec b/isomd5sum.spec
index 3f2a3e1..1bf7015 100644
--- a/isomd5sum.spec
+++ b/isomd5sum.spec
@@ -3,7 +3,7 @@
 Summary: Utilities for working with md5sum implanted in ISO images
 Name:    isomd5sum
 Version: 1.2.4
-Release: 1%{?dist}
+Release: 2%{?dist}
 Epoch: 1
 License: GPL-2.0-or-later
 
@@ -12,6 +12,8 @@ License: GPL-2.0-or-later
 Url:     %{forgeurl}
 Source0: %{forgesource}
 
+Patch0001: 0001-Revert-Fix-checksum-failure-with-small-isos.patch
+
 BuildRequires: gcc
 BuildRequires: popt-devel
 BuildRequires: python3-devel
@@ -67,6 +69,10 @@ PYTHON=%{__python3} make DESTDIR=$RPM_BUILD_ROOT install-bin install-devel insta
 %{python3_sitearch}/pyisomd5sum.so
 
 %changelog
+* Mon Apr 29 2024 Brian C. Lane <bcl@redhat.com> - 1.2.4-2
+- Revert small iso fix, it resulted in incorrect checksums
+  Resolves: rhbz#2277398
+
 * Fri Feb 16 2024 Brian C. Lane <bcl@redhat.com> - 1.2.4-1
 - New Version 1.2.4 (bcl)
 - Add support for riscv64 (davidlt)
diff --git a/tests/smoke.sh b/tests/smoke.sh
index 1f2f20e..ce667b2 100755
--- a/tests/smoke.sh
+++ b/tests/smoke.sh
@@ -8,8 +8,12 @@ mkisofs -o test.iso isocontent
 
 # Implant and check md5 sum
 implantisomd5 test.iso
-checkisomd5 --verbose test.iso
+checkisomd5 --verbose test.iso 2>&1 | tee test.run.log
+
+echo "Check implanted checksum for 1.2.4-1 checksum bug"
+grep ';FR' test.run.log && exit 1
 
 # Destroy testing iso image
 rm -rf ./isocontent
 rm test.iso
+rm test.run.log