How to improve speed to download ulog files in SD-card

Hi all,
In our flights, we create huge size of ulog files per one flight.
Downloading the ulog file takes a long time on MAVLINK protcol via USB I/F.
For example, 100 MByte ulog files are created in one flight,
but it takes about 12 minutes to download to my PC.
We know that the best solution is to remove the SD card from the FC and insert it into the PC to retrieve the ulog files.
However, our UAV cannot access the SD card because the FC board is in the case.
In this situation, we want to improve the download speed of ulog files more than twice.
Please let me know if you have any solution.
I look forward to hearing from you. Thanks.