well I've installed the new uboot with nand-sata-install on the sd and now the 4 cores are online, thanks !
root@beelinkx2:~# lscpu
Architecture: armv7l
Byte Order: Little Endian
CPU(s): 4
On-line CPU(s) list: 0-3
Thread(s) per core: 1
Core(s) per socket: 4
Socket(s): 1
Vendor ID: ARM
Model: 5
Model name: Cortex-A7
Stepping: r0p5
CPU max MHz: 1008.0000
CPU min MHz: 648.0000
BogoMIPS: 118.58
Flags: half thumb fastmult vfp edsp neon vfpv3 tls vfpv4 idiva idivt vfpd32 lpae evtstrm
Now I have another small problem, when I try to copy the image to the internal nand I get this
Partition too small. Needed: 5172 MB Avaliable: MB
I've read that this particular nand is not fully supported, but I'd like to know if there's a workaround....
[ 2.603888] mmc2: new DDR MMC card at address 0001
[ 2.608190] mmcblk2: mmc2:0001 VICO 7.22 GiB
[ 2.619250] mmcblk2boot0: mmc2:0001 VICO 4.00 MiB
[ 2.628928] mmcblk2boot1: mmc2:0001 VICO 4.00 MiB
[ 7.096172] I/O error, dev mmcblk2boot0, sector 8064 op 0x0:(READ) flags 0x0 phys_seg 1 prio class 2
[ 7.096216] Buffer I/O error on dev mmcblk2boot0, logical block 1008, async page read
[ 7.264253] sunxi-mmc 1c11000.mmc: data error, sending stop command
[ 7.264303] sunxi-mmc 1c11000.mmc: send stop command failed