diff --git a/0304-10_linux.in-Check-if-petitboot-sysfs-has-a-valid-ver.patch b/0304-10_linux.in-Check-if-petitboot-sysfs-has-a-valid-ver.patch
new file mode 100644
index 0000000..79c805f
--- /dev/null
+++ b/0304-10_linux.in-Check-if-petitboot-sysfs-has-a-valid-ver.patch
@@ -0,0 +1,67 @@
+From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
+From: Javier Martinez Canillas <javierm@redhat.com>
+Date: Wed, 10 Mar 2021 12:50:15 +0100
+Subject: [PATCH] 10_linux.in: Check if petitboot sysfs has a valid version
+
+The script assumes that the petitboot sysfs entry contains a valid version
+number, but this is not always the case. For example, on a Talos II system
+a user reported that contained the following value:
+
+$ cat /sys/firmware/devicetree/base/ibm,firmware-versions/petitboot
+0ed84c0-p94177c1
+
+This lead to the script wrongly trying to compare these hashes as if they
+were integers values, which caused the following error when re-generating
+the GRUB configuration file:
+
+/etc/grub.d/10_linux: line 234: test: 0ed84c0-p94177c1: integer expression expected
+/etc/grub.d/10_linux: line 235: test: 0ed84c0-p94177c1: integer expression expected
+
+Check that the major and minor values are integers before attempting to do
+the comparison. If these aren't numbers, then generate the menu with a set
+of menuentry commands, since there's no way to know the petitboot version.
+
+Resolves: rhbz#1921479
+
+Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>
+---
+ util/grub.d/10_linux.in | 19 ++++++++++++-------
+ 1 file changed, 12 insertions(+), 7 deletions(-)
+
+diff --git a/util/grub.d/10_linux.in b/util/grub.d/10_linux.in
+index e61b6c94f11..b9426eb2e2e 100644
+--- a/util/grub.d/10_linux.in
++++ b/util/grub.d/10_linux.in
+@@ -223,20 +223,25 @@ if [ "x${GRUB_ENABLE_BLSCFG}" = "xtrue" ]; then
+   arch="$(uname -m)"
+   if [ "x${arch}" = "xppc64le" ] && [ -d /sys/firmware/opal ]; then
+ 
++      BLS_POPULATE_MENU="true"
+       petitboot_path="/sys/firmware/devicetree/base/ibm,firmware-versions/petitboot"
+ 
+       if test -e ${petitboot_path}; then
+           read -r -d '' petitboot_version < ${petitboot_path}
+           petitboot_version="$(echo ${petitboot_version//v})"
+-          major_version="$(echo ${petitboot_version} | cut -d . -f1)"
+-          minor_version="$(echo ${petitboot_version} | cut -d . -f2)"
+ 
+-          if test -z ${petitboot_version} || test ${major_version} -lt 1 || \
+-                  test ${major_version} -eq 1 -a ${minor_version} -lt 8; then
+-              BLS_POPULATE_MENU="true"
++	  if test -n ${petitboot_version}; then
++              major_version="$(echo ${petitboot_version} | cut -d . -f1)"
++              minor_version="$(echo ${petitboot_version} | cut -d . -f2)"
++
++              re='^[0-9]+$'
++              if [[ $major_version =~ $re ]] && [[ $minor_version =~ $re ]] &&
++                 ([[ ${major_version} -gt 1 ]] ||
++                  [[ ${major_version} -eq 1 &&
++                     ${minor_version} -ge 8  ]]); then
++                  BLS_POPULATE_MENU="false"
++              fi
+           fi
+-      else
+-          BLS_POPULATE_MENU="true"
+       fi
+   fi
+ 
diff --git a/grub.patches b/grub.patches
index 4135406..84ecf0e 100644
--- a/grub.patches
+++ b/grub.patches
@@ -301,3 +301,4 @@ Patch0300: 0300-appended-signatures-documentation.patch
 Patch0301: 0301-ieee1275-link-appended-signature-enforcement-to-ibm-.patch
 Patch0302: 0302-at_keyboard-use-set-1-when-keyboard-is-in-Translate-.patch
 Patch0303: 0303-Add-at_keyboard_fallback_set-var-to-force-the-set-ma.patch
+Patch0304: 0304-10_linux.in-Check-if-petitboot-sysfs-has-a-valid-ver.patch
diff --git a/grub2.spec b/grub2.spec
index 103e1b9..34170bf 100644
--- a/grub2.spec
+++ b/grub2.spec
@@ -14,7 +14,7 @@
 Name:		grub2
 Epoch:		1
 Version:	2.04
-Release:	38%{?dist}
+Release:	39%{?dist}
 Summary:	Bootloader with support for Linux, Multiboot and more
 License:	GPLv3+
 URL:		http://www.gnu.org/software/grub/
@@ -551,6 +551,10 @@ mv ${EFI_HOME}/grub.cfg.stb ${EFI_HOME}/grub.cfg
 %endif
 
 %changelog
+* Thu Mar 11 2021 Javier Martinez Canillas <javierm@redhat.com> - 2.04-39
+- Fix config file generation failing due invalid petitboot version value
+  Resolves: rhbz#1921479
+
 * Fri Mar 05 2021 Javier Martinez Canillas <javierm@redhat.com> - 2.04-38
 - Fix keyboards that report IBM PC AT scan codes (rmetrich)