: Detailed technical reference manuals and release notes are typically restricted to registered customers with valid maintenance contracts through the Broadcom docSAFE portal Security and Maintenance Vulnerability Management
Broadcom and OEMs (TP-Link, Netgear, Zyxel, Huawei) use a pattern like: bcm63381b0 firmware
Broadcom, following the whims of the ISP market, shipped these chips with locked bootloaders. The firmware was proprietary. The goal was to create a "black box"—a device that did exactly what the ISP wanted, nothing more, and certainly nothing less. If the ISP wanted to rent you a router, they didn't want you installing custom software on it. They wanted you to rent their software. : Detailed technical reference manuals and release notes