diff --git a/cook/ingredients/hypervisor/amdcpu.ks b/cook/ingredients/hypervisor/amdcpu.ks
index 25993a3..9c48440 100644
--- a/cook/ingredients/hypervisor/amdcpu.ks
+++ b/cook/ingredients/hypervisor/amdcpu.ks
@@ -2,8 +2,27 @@
 
 %post --nochroot --log=/mnt/sysimage/root/hypervisor-amdcpu-post.log # Beginning of %post section. Those commands are executed outside the chroot environment. Logging is enabled to help with post-installation troubleshooting
 
-sed -i 's/\(quiet\)/\1 iommu=pt rd.driver.pre=vfio-pci/i' /mnt/sysimage/etc/default/grub # Load kernel modules in GRUB. 
+# Kernel arguments cannot be attached to a single canonical location at %post time:
+# anaconda always creates /etc/kernel/cmdline (kernel-install source for both
+# systemd-boot and GRUB+BLS layouts), but GRUB+BLS boot entries have already been
+# generated from it by the kernel package scriptlets, and non-BLS flows still read
+# /etc/default/grub. Update every surface idempotently, guarded by file existence.
 
-echo "options kvm_amd nested=1" >> /mnt/sysimage/etc/modprobe.d/kvm.conf # Add support for nested virtualization
+IOMMU_ARGS="iommu=pt rd.driver.pre=vfio-pci"
+
+if [ -f /mnt/sysimage/etc/kernel/cmdline ]; then # kernel-install source (systemd-boot now, GRUB+BLS for future kernels)
+    grep -q "iommu=pt" /mnt/sysimage/etc/kernel/cmdline || echo " $IOMMU_ARGS" >> /mnt/sysimage/etc/kernel/cmdline # Append IOMMU arguments once
+fi
+
+if [ -f /mnt/sysimage/etc/default/grub ]; then # GRUB: arguments for grub.cfg-based boot flows
+    grep -q "iommu=pt" /mnt/sysimage/etc/default/grub || sed -i "s/\(quiet\)/\1 $IOMMU_ARGS/i" /mnt/sysimage/etc/default/grub # Append IOMMU arguments once
+fi
+
+for bls_entry in /mnt/sysimage/boot/loader/entries/*.conf; do # Already-generated boot entries share one "options" line shape
+    [ -e "$bls_entry" ] || continue # Nothing matched: the glob stays literal
+    grep -q "iommu=pt" "$bls_entry" || sed -i "s/^\(options .*\)/\1 $IOMMU_ARGS/" "$bls_entry" # Patch the options line of each entry once
+done
+
+grep -q "nested=1" /mnt/sysimage/etc/modprobe.d/kvm.conf 2>/dev/null || echo "options kvm_amd nested=1" >> /mnt/sysimage/etc/modprobe.d/kvm.conf # Add support for nested virtualization on AMD CPUs, exactly once
 
 %end # End of the %post section