RCM6700 6 serial ports and fat

Hi all

I have a problem using an RCM6700 with the 6 serial ports enabled and the fat filesystem. In datasheets i saw that rcm uses the serial port B 
pins to drive the serial flash (PD4,PD5,PD6). In IOconfig i have change the serial portB to pins PC4,PC5. In this configuration if the serial port B is closed, the fat works fine but if is opened some times the fat works ans some times blocks (is in blocking mode) randomly.
There is another define that i missed? I will test to open the portB only when i need it (when i use it i dont need the fat) but is a safe method ?

Below is all the definitions

#define AINBUFSIZE  31
#define AOUTBUFSIZE  31
#define SERA_TXPORT  PCDR
#define ADRIVE_TXD  6
#define SERA_RXPORT  PCDR
#define ADRIVE_RXD  7
#define BINBUFSIZE  31
#define BOUTBUFSIZE  31
#define SERB_TXPORT  PCDR
#define BDRIVE_TXD  4
#define SERB_RXPORT  PCDR
#define BDRIVE_RXD  5
#define CINBUFSIZE  31
#define COUTBUFSIZE  31
#define SERC_TXPORT  PCDR
#define CDRIVE_TXD  2
#define SERC_RXPORT  PCDR
#define CDRIVE_RXD  3
#define DINBUFSIZE  31
#define DOUTBUFSIZE  31
#define SERD_TXPORT  PCDR
#define DDRIVE_TXD  0
#define SERD_RXPORT  PCDR
#define DDRIVE_RXD  1
#define EINBUFSIZE  31
#define EOUTBUFSIZE  31
#define SERE_TXPORT  PEDR
#define EDRIVE_TXD  6
#define SERE_RXPORT  PEDR
#define EDRIVE_RXD  7
#define FINBUFSIZE  31
#define FOUTBUFSIZE  31
#define SERF_TXPORT  PDDR
#define FDRIVE_TXD  2
#define SERF_RXPORT  PEDR
#define FDRIVE_RXD  3

and the settings


   serAopen(9600L);
   WrPortI(SACR,&SACRShadow, 0x01);
   serBopen(9600L);
   WrPortI(SBCR,&SBCRShadow, 0x01);
   serCopen(2400L);
   WrPortI(SCCR,&SCCRShadow, 0x01);
   serDopen(2400L);
   WrPortI(SDCR,&SDCRShadow, 0x01);
   serEopen(2400L);
   WrPortI(SECR,&SECRShadow, 0x21);
   serFopen(2400L);
   WrPortI(SFCR,&SFCRShadow, 0x11);

   WrPortI(PBDDR,&PBDDRShadow,0xDC);     // Port B Input and output Pins
   WrPortI(PCFR,&PCFRShadow,0x55);     // Serial Port C
   WrPortI(PDALR,&PDALRShadow,0x30);     // Serial Port F
   WrPortI(PDDDR,&PDDDRShadow,0x64);     // Serial Port F    
   WrPortI(PDFR,&PDFRShadow,0x04);     // Serial Port F
   WrPortI(PEAHR,&PEAHRShadow,0x30);     // Serial Port E
   WrPortI(PEDDR,&PEDDRShadow,0x40);     // Serial Port E
   WrPortI(PEFR,&PEFRShadow,0x40);     // Serial Port E
   WrPortI(SACR,&SACRShadow,0x01);     // Serial Port A
   WrPortI(SBCR,&SBCRShadow,0x01);     // Serial Port B
   WrPortI(SCCR,&SCCRShadow,0x01);     // Serial Port C
   WrPortI(SDCR,&SDCRShadow,0x01);     // Serial Port D
   WrPortI(SECR,&SECRShadow,0x21);     // Serial Port E
   WrPortI(SFCR,&SFCRShadow,0x11);     // Serial Port F

Thank's

Akis