求助：优酷K1无法进入刷机模式

优酷K1盒子，在用安卓5.1，在刷回4。4的时候，出了点问题。就是在等待重启的时候，电脑死机了。然后就无法进入loader 模式了，现在开机蓝灯黑屏。按REST键加电，电脑没反应。TTL串口log信息如下，哪位高人指点一下，有解吗？

DDR Version 1.00 20141007
In
Channel a: DDR3 200MHz
Bus Width=32 Col=10 Bank=8 Row=14 CS=1 Die Bus-Width=16 Size=512MB
Channel b: DDR3 200MHz
Bus Width=32 Col=10 Bank=8 Row=14 CS=1 Die Bus-Width=16 Size=512MB
Memory OK
Memory OK
OUT


U-Boot 2014.10-RK3288-02 (Oct 30 2014 - 09:27:41)

CPU: rk3288
CPU's clock information:
    arm pll = 600000000HZ
    periph pll = 300000000HZ
    ddr pll = 200000000HZ
    codec pll = 594000000HZ
Board:  Rockchip platform Board
DRAM:  Found dram banks:1
Adding bank:0000000000000000(0000000040000000)
128 MiB
storage init OK!
Using default environment

GetParam
check parameter success
Unknow param: MACHINE_MODEL:RKM MK902II!
Unknow param: MACHINE_ID:007!
Unknow param: MANUFACTURER:RK3288!
Unknow param: PWR_HLD: 0,0,A,0,1!
failed to prepare fdt from boot!
power key: bank-0 pin-5
can't find dts node for ricoh619
pmic:act8846
Can't find dts node for fuel guage cw201x
SecureBootEn = 0, SecureBootLock = 0

#Boot ver: 2014-10-30#2.17
empty serial no.
no fuel gauge found
no fuel gauge found
read logo_on switch from dts [1]
can't find power_ctr node for lcdc0
pll_src = 0, dclk_hz = 148500000, dclk_div = 4
checkKey
vbus = 1
rockusb key pressed.

高手快来呀