I think I might have solved the occasional problem with lockups in the SDL console (C-version, converted to single camera), here's my code to receive the image (no lockups for a whole day):
 
Code:

// look for frames
while (!imageReady) {	
	if (!imageReady) {
		nrSocketsReady = SDLNet_CheckSockets(socSet, TIMEOUT);
		if (nrSocketsReady == -1) {
			printf("SDLNet_CheckSockets: %s\n", SDLNet_GetError());
			perror("SDLNet_CheckSockets");
		}
		else if (nrSocketsReady > 0) {
			if (SDLNet_CheckSockets(socSet, TIMEOUT)) {
				if (SDLNet_SocketReady(socSet)) {
					result = SDLNet_TCP_Recv(tcpsock, buf, MTU);
					memcpy(imageBuf+index, buf, result);
					index += result;
					if ((buf[result-2] == -1) && (buf[result-1] == -39))
						imageReady = 1;
				}
			}
		}
		else {
			printf("\n\rNo sockets ready.\n\r");
			break;
		}
	}
} 

 
If there's a timeout, the current frame will be skipped, and no update will occur until the request of a new frame.

I've added support for sending commands directly through the SDL console to the SRV (single camera) and the reply is printed in the linux console. The full source and a make script can be downloaded HERE.
 
Any comments or questions are very welcome!