Thanks for your interest. Regarding the requirements you mentioned, after preliminary evaluation, some of these requirements may indeed involve firmware customization. However, disabling HFP can be achieved directly via AT commands, configuration with the AT+PROFILE command. For more information about the FSC-BT1026B, you can refer to the FSC-BT1026x User Guide. This document includes hardware design notes, functional descriptions, AT command sets, rapid development kits, typical application development examples, and more.
Before that, I wonder if I could obtain more details regarding your project:
What is the product of your project, and what functions will be achieved with the FSC-BT1026B module?
Is your project an open-source project? Will it be released on GitHub or other open-source platforms?