To be safe, I followed the advice suggested by jsmiddleton4 (factory reset of Tomato --> reboot --> enter recovery mode --> flash to stock Asus firmware using Asus restoration software --> flash to Merlin per normal). Worked flawlessly.
Thank you both for the help.
Question: I am currently running Tomato by Shibby (Firmware 1.28.0000 -138 K26ARM USB AIO-64K) on an Asus RT-AC68W router. I would like to move to AsusWRT-Merlin. Can I upgrade as normal using the "upgrade" tab of the Shibby menu and uploading the Merlin firmware? Or do I first need to use...