EVM5515 NAND Flash Error

Hello

I have been trying to flash my EVM5515 with a program of my own.
So after reading a piece of threads on the forum, I first tried to flash with an example. So in a prompt I launched :
"C:\Program Files\Texas Instruments\ccsv4\tools\compiler\c5500\bin\hex55" -boot -v5505 -serial8 -b oled.out -o oled.bin
Then in code composer studio, I launched programmer.out (connect target, load program C:\Program Files\Texas Instruments\ccsv4\emulation\boards\evm5515_v1\tests\demo\programmer.out)
In the console, I got :
Choose the device...
0XX - CPLD setup only
1x - NAND Flash [CSx: 2,3,4,5]
2x - NOR Flash [CSx: 2,3,4,5]
3x - SPI EEPROM [x=1: EVM, x=2: USB Stick]
4 - IIC EEPROM
5 - MMC;  6 - SD
And I entered :
C:\Apps\TI_bins\oled.bin

I got a lot of messages, until it indicated that it was done. So I powered of the thing, unplugged the USB, powered it on, then the oled program launched well.
Thus I was confident the method was good.
Then I tried with the same method, all seemed to be well. But now when I power the EVM on, the screen stays dark and I have no sound, so I think the program is not running.

I can still run programs in debug mode, but I have a lot of error messages and I can't flash the board any more (process stop at NAND Flash...).

The error messages are :
When connecting :
    Error connecting to the target:
    Error 0x80000244/-1143
    Fatal Error during: Register, Initialization, OCS,
    The memory at 0x00000000 continually indicated it was 'not ready'
    All memory operations currently in progress were aborted in order
    to regain control of the processor.
    This is considered a catastrophic event, but the debugger should
    still be able to access memory and CPU registers.
    System state has been altered.  It is strongly advised
    that the processor should be reset before resuming execution,
I click on retry, and after three seconds :
    Trouble Writing Memory Block at 0x1021 on Page 2 of Length 0x1:
    Error 0x80000002/-1143
    Fatal Error during: Memory,
    The memory at 0x00002044 continually indicated it was 'not ready'
    All memory operations currently in progress were aborted in order
    to regain control of the processor.
    This is considered a catastrophic event, but the debugger should
    still be able to access memory and CPU registers.
    System state has been altered.  It is strongly advised
    that the processor should be reset before resuming execution,
I click on Ok and all seems well (for I can launch programs in debug mode).

So, is there a way to reset the NAND flash or to skip the NAND boot in order to boot correctly on the standard EVM demo ?

Thanks in advance for any help or suggestion