Gang He developed a PSRAM-based heap expansion for the 78/xiaozhi-sf32 repository, focusing on improving audio and network performance in embedded systems. He enabled PSRAM cache write-back and migrated audio data storage to PSRAM, which freed up the main heap for network data and reduced memory pressure. Working in C and leveraging skills in audio processing, memory management, and RTOS, Gang He increased the opus heap and updated the memory allocator to utilize a larger heap. This engineering effort enhanced resource management and throughput, resulting in more stable performance for audio processing and network operations under demanding conditions.