Some Questions about Simtrace

Dear Sir or Madam: I've bought two simtrace development boards two months ago in order to research the communication between the SIM-card and the mobile phone. However, recently when I need to analyse the packet which contains CK and IK, I sadly found that the packet was not captured every time. Mostly it returns as a malformed packet in the wireshark, which blocks my future studying. I read the user manual and it says that for some high speed cards the firmware can lose bytes, and to solve that we can reduce the size of the buffer. So I'm writing to ask the specific steps to reduce the buffer and recompile the firmware, and I've tried by myself but I couldn't find a proper toolchain which includes a GCC but not an EABI. I'm looking forward to your reply. Best wishes! Yours, sincerely Luna-Qi