diff --git a/.grubby.checksum b/.grubby.checksum
new file mode 100644
index 0000000000000000000000000000000000000000..7607ae82d3b48b2b86208ede958103a72f4ef382
--- /dev/null
+++ b/.grubby.checksum
@@ -0,0 +1 @@
+4f379bba6e7d145c5c68b0c7f7147052f13e6ff234ae2a3a5068c6d793052df9
diff --git a/.grubby.metadata b/.grubby.metadata
index 6085fc6e49c2fa76ad7d602c12f84fdc84d87e7a..e6061b76470cac822d3b26bb594591e589fe2d75 100644
--- a/.grubby.metadata
+++ b/.grubby.metadata
@@ -1 +1 @@
-97ae8d113b74538c05f05083dcff4f44012fd0cd SOURCES/8.40-1.tar.gz
+85f1c678484f74c8978e8643451594967defce463a86c35cb1ee56d12767a9df SOURCES/8.40-1.tar.gz
diff --git a/SOURCES/grubby-bls b/SOURCES/grubby-bls
index 3c2544a35788f1f03c0e95d8dda6328c882c0f87..fef62db246946840ebdbe88d460f5469f1780cd7 100755
--- a/SOURCES/grubby-bls
+++ b/SOURCES/grubby-bls
@@ -500,7 +500,7 @@ update_bls_fragment() {
             if [[ -n $old_args ]]; then
                 opts="$(update_args "${old_args}" "${remove_args}" "${add_args}")"
                 opts="$(echo "$opts" | sed -e 's/\//\\\//g')"
-                sed -i -e "s/^GRUB_CMDLINE_LINUX.*/GRUB_CMDLINE_LINUX=\\\"${opts}\\\"/" "${grub_etc_default}"
+                sed -i -e "s/^GRUB_CMDLINE_LINUX=.*/GRUB_CMDLINE_LINUX=\\\"${opts}\\\"/" "${grub_etc_default}"
             fi
         fi
 
diff --git a/SPECS/grubby.spec b/SPECS/grubby.spec
index d83cd91973c8847008609142a188251d1eb15dea..658ec91779c5130f8d9e407f98efed1077a6e189 100644
--- a/SPECS/grubby.spec
+++ b/SPECS/grubby.spec
@@ -1,6 +1,6 @@
 Name: grubby
 Version: 8.40
-Release: 63%{?dist}
+Release: 64%{?dist}
 Summary: Command line tool for updating bootloader configs
 License: GPLv2+
 URL: https://github.com/rhinstaller/grubby
@@ -131,6 +131,10 @@ current boot environment.
 %{_mandir}/man8/*.8*
 
 %changelog
+* Wed Jan 10 2024 Marta Lewandowska <mlewando@redhat.com> - 8.40-64
+- Do not overwrite all vars that start with GRUB_CMDLINE_LINUX
+- Resolves: #RHEL-21301
+
 * Tue Feb 21 2023 Marta Lewandowska <mlewando@redhat.com> - 8.40-63
 - remove root= when not copying default
 - Resolves: #2127453