I followed the instructions of Titiris and reloaded the nk.nb0 file (loady 0x0361000 115200) of the firmware (and also tried different versions of firmware) but the same problem remains: U-Boot stops at the same place.
So bought brand new NAND memory, replaced the old NAND by the new one on the board and redid the same process (loady 0x0361000 115200). Now U-boots goes further but is kind of stock in a loop:
BALDWIN_DDI: cBaldwinHwIf::Init: Scope successfully identified.
Exception 'Data Abort' (4): Thread-Id=04100002(pth=8371a340), Proc-Id=00400002(pprc=816a8308) 'NK.EXE', VM-active=01e40002(pprc=87fcbeac) 'udevice.exe'
PC=c08fa088(baldwin_ddi.dll+0x0000a088) RA=c08fa07c(baldwin_ddi.dll+0x0000a07c) SP=d137f660, BVA=00000000
Exception 'Data Abort' (4): Thread-Id=04100002(pth=8371a340), Proc-Id=00400002(pprc=816a8308) 'NK.EXE', VM-active=01e40002(pprc=87fcbeac) 'udevice.exe'
PC=c01a5d84(gwes.dll+0x00055d84) RA=c01a5d6c(gwes.dll+0x00055d6c) SP=d137fdd8, BVA=00000104
Autonegociation Start (ticks=4633)
+StartAutoNegotiation: pDeviceContext 0xd05694c0
Exception 'Raised Exception' (-1): Thread-Id=047a0002(pth=8372bc20), Proc-Id=03a50006(pprc=837eeee0) 'recoverInfiniiVision.exe', VM-active=03a50006(pprc=837eeee0) 'recoverInfiniiVision.exe'
PC=400233d0(coredll.dll+0x000133d0) RA=803782c8(kernel.dll+0x000062c8) SP=0005fd1c, BVA=00000000
Exception 'Raised Exception' (-1): Thread-Id=04820002(pth=8372bc20), Proc-Id=03a5000a(pprc=837eeee0) 'recoverInfiniiVision.exe', VM-active=03a5000a(pprc=837eeee0) 'recoverInfiniiVision.exe'
PC=400233d0(coredll.dll+0x000133d0) RA=803782c8(kernel.dll+0x000062c8) SP=0005fd1c, BVA=00000000
Exception 'Raised Exception' (-1): Thread-Id=048a0002(pth=8372bc20), Proc-Id=03a5000e(pprc=837eeee0) 'recoverInfiniiVision.exe', VM-active=03a5000e(pprc=837eeee0) 'recoverInfiniiVision.exe'
PC=400233d0(coredll.dll+0x000133d0) RA=803782c8(kernel.dll+0x000062c8) SP=0005fd1c, BVA=00000000