Cause: New default radio settings. Solution: Change the 2.4GHz channel from Auto to a fixed channel (1, 6, or 11). Set 5GHz to a non-DFS channel like 36 or 149. Also, disable "Wi-Fi Agile Multiband" if present.
Do NOT download firmware from random forums or file-sharing sites. Only use legitimate sources. dsl-3788 firmware
To understand the firmware, one must understand the underlying hardware. The DSL-AC68U is powered by the Broadcom BCM63138 SoC (System on Chip). Cause: New default radio settings
The BCM63138 is a unique architecture requiring specific Broadcom Kernel patches, often making mainline Linux kernel support difficult and locking the device into vendor-specific binary blobs. Do NOT download firmware from random forums or
Even with correct preparation, things can go wrong. Here is how to fix them.