render_buf was too big
It was misdeclared as a array of pointers (uint8_t*[]) and there where too many elements (64 * 1024) instead of (64 * 1024 - 1).
It was misdeclared as a array of pointers (uint8_t*[]) and there where too many elements (64 * 1024) instead of (64 * 1024 - 1).