I understand you're looking for custom firmware for the Huawei B535-232 router. However, I need to provide an important disclaimer before addressing your request:

• Huawei AT command interface (serial over USB)
• Third-party tools like Huawei Band Tool, LTE H Monitor, or HCOS

Considerations and Precautions

Networking Enhancements

: Support for VPNs (OpenVPN), TTL/Hop Limit mangling to bypass tethering limits, and band selection menus.