Yes, mounting the USB disk partition to "/opt" was a key part of the solution that I found last night after I had set up my cousin's new
RT-AX86S which is replacing their 6-year-old RT-AC68U router. He's got simple home network needs (family of 4, only 2 IoT devices, laptops, iPads, ... about a dozen devices in total), and so far there has been no need to install the Asuswrt-Merlin F/W on it. It's currently running the latest ASUS stock
388.20566 F/W.
I had written before a script that I used to install Entware on the
GT-AC5300 &
RT-AC86U running ASUS stock F/W. On the
RT-AX86S (and likely on other AX routers), the problem is that "/opt" already exists as a directory (*not* a symbolic link), so I modified my script to mount the USB disk "entware" directory to "/opt" before starting the actual Entware generic installer. It all worked very well. I tested my script a few times with other alternatives and eventually found this was the best solution, IMO, so far. In addition, there's a "scripts" folder inside the existing "/opt" directory which contains some script files. To avoid any possible issues, I copy the "/opt/scripts" folder to the "entware" directory in case "something" in the F/W calls those scripts.
BTW, I install Entware primarily to get some useful tools missing from the F/W (e.g. nano, htop, diff, tcpdump, lsof, fuser, ltrace, etc.), and especially now because SCP is missing as well. IMO, these tools are essential to have readily available for quick diagnostic purposes, so my script *automatically* installs the corresponding packages and modifies the "/opt/etc/profile" as I recommended before on this <
post>. It also sets the current SSH port number for the Entware's SCP tool to work as expected (e.g. with WinSCP). After my script successfully completes, the Entware installation is ready to go with some of the tools that I want available on the router.
I can provide my script file if anyone is interested in trying it with their AX routers (or AC types as well).
Here's a screenshot from the
RT-AX86S with Entware:
View attachment 44755