vershov 
I have got Mini6410 (1048) board with Linux 2.6.38-FriendlyARM pre-installed. I have slightly modify boot process removing unneeded software bundle: netd, httpd, leds, alsaconf and qtopia. I'm trying to test data flow writing to SD card. Test data is file of 594339 UDP packets (782150876 bytes). I have also increase network interface internal buffers size (using sysctl and invoking setsockopt from my tools): sysctl -w net.core.wmem_max=16000000 sysctl -w net.core.rmem_max=16000000 My setup is as follows: - A: Mini6410 with mounted SD card (32GB SDHC card class 10, FAT32) and tool that is received data from UDP port opened. - B: Linux box with simple tool that is produced 10 Mbit/s data stream (MPEG TS) and is sent it to remote UDP port. - C: Another Linux box Test 1: Send test data file from B to A. Result 1: All packets is came (0% lost packets) – OK Test 2: Send test data file from B to A. A do analyze data as per TR 101290 Result 2: All packets is came (0% lost packets) and analyzed – OK Test 3: Send test data file from B to A. A do route all data to C Result 3: All packets is came to A all packets is came to C (0% lost packets) – OK Test 4: Send test data file from B to A. A writes all data to the file at SD card Result 4: I have 80% of the lost packets – FAILED I have also tried it with several tweaks – result is the same: sysctl -w vm.drop_caches=2 sysctl -w vm.dirty_expire_centisecs=500 sysctl -w vm.dirty_background_ratio=5 sysctl -w vm.dirty_ratio=10 sysctl -w vm.min_free_kbytes=721 The same tests at another board (EV-iMX287 Alienboard ARM926) shows 0% lost packets and all data was written at the same SD card. Could anybody help me in resolving this issue? Any ideas are welcome. (I could provide tools source code if needed). Thanks, Vlad.