A33 tablet u-boot not boot (fel +sdbreakout).

Hi,
I'm trying to boot an A33 tablet , i buy sdcard breakout and enable sd card uart in .config using (UART0 on MicroSD breakout board).

I used q8_a33_tablet_1024x600_defconfig as base.

I read serial port output from BOOT0 and finally "eraly jump fel" message so i'm sure sdcard breakout work.

and from my linux 16.04 command line

u-boot-2016.09# sunxi-fel -v ver
AWUSBFEX soc=00001667(A33) 00000001 ver=0001 44 08 scratchpad=00007e00 00000000 00000000

u-boot-2016.09# sunxi-fel -v uboot u-boot-sunxi-with-spl.bin Stack pointers: sp_irq=0x00002000, sp=0x00005E08 MMU is not enabled by BROM
=> Executing the SPL... done.
libusb usb_bulk_send error -7

u-boot-2016.09#

Nothing happen!!

My tablet not boot direct from sdcard obviously(only installed android work), what can do for deeper debug ?

I see that there is a early uart debug option in .config but ask parameters that i don't know.

Thanks