How do I make a cheat-code permanent on Knoppix 8.6.1?

**Summary:** How do I make the following cheat-code permanent on knoppix 8.6.1 on usb stick, because filesystem type is iso9660 (read-only) and won't let me edit /mnt-system/boot/isolinux/isolinux.cfg. **Cheat code entered at boot prompt:** knoppix xmodule=vesa **Full Details:** I've just put knoppix 8.6.1 on a usb stick (persistence was there by default). But X Window won't display unless I enter the cheat-code "knoppix xmodule=vesa" at the initial boot prompt. Incidentally, when using Knoppix 7.7.1 on a usb stick, on the EXACT SAME laptop (Acer Aspire 5755G), I don't need the cheat-code. I'd like to **not have to type the cheat-code in every time** I boot the 8.6.1, and believe that I can achieve that by adding "xmodule=vesa" as a kernel parameter on an "APPEND" line in /boot/isolinux/isolinux.cfg. I can get to that file using the path /mnt-system/boot/isolinux/isolinux.cfg. **But it won't let me write** to that file because /mnt-system is mounted read only. When I try to remount /mnt-system as read-write, it says "write-protected." /UNIONFS **is** mounted as read-write, but the path /UNIONFS/boot/isolinux/ does not exist. I understand that because partition 1 (the main Knoppix system) is filesystem type iso9660*, that it is by definition read-only. (*On which I believe /boot/isolinux/isolinux.cfg sits). **Main Question:** So could you tell me please, what method I need to use to make my cheat-code permanent? **Reason for Using 8.6.1:** I'm trying out 8.6.1 because it has a newer kernel than 7.7.1, and I've read that a newer kernel might fix my problem of downloads halting when the lid is closed. I've already tried many lid disabling methods, but none of them prevent the downloading from halting.