disable kexec-syscall-auto flag on old kernels

nix/kexec-installer/kexec-run.sh

@@ -54,8 +54,15 @@ done
 
 find . | cpio -o -H newc | gzip -9 >> "$SCRIPT_DIR/initrd"
 
+kexecSyscallFlags=""
+# only do kexec-syscall-auto on kernels newer than 6.0.
+# On older kernel we often get errors like: https://github.com/nix-community/nixos-anywhere/issues/264
+if ! printf "%s\n" "6.1" "$(uname -r)" | sort -c -V; then
+  kexecSyscallFlags="--kexec-syscall-auto"
+fi
+
 if ! "$SCRIPT_DIR/kexec" --load "$SCRIPT_DIR/bzImage" \
-  --kexec-syscall-auto \
+  "$kexecSyscallFlags" \
   --initrd="$SCRIPT_DIR/initrd" --no-checks \
   --command-line "init=$init $kernelParams"; then
   echo "kexec failed, dumping dmesg"