simtrace let sim cards

I have simtrace working with a debian VM. It works consistently with 2G cards, but stop working with 3G let cards. Seems to boot and then stops. Has this been fixed? I read about reducing the buffer in the firmware, but this is a challenge creating a bin file as arm-elf is no longer supported and creating a cross compiling toolchain with modern compiler is posing problems. Do you have a bin firmware file with a reduced buffer that works with sim lte cards?