Linux/OMAP-L138: which u-boot file should we use after we compiled uboot package?

Part Number:OMAP-L138

Tool/software: Linux

Hello,

We are working with omap-L138 in processor sdk. after we compiled it by using commandline:

make CROSS_COMPILE=arm-linux-gnueabi- O=omap-l138 omapl138_lcdk_defconfig
make CROSS_COMPILE=arm-linux-gnueabi- O=omap-l138

we got u-boot.bin, uboot.img, u-boot.ais, u-boot-nodtb.bin etc. 

We've read the guide in: http://processors.wiki.ti.com/index.php/Processor_SDK_Linux_Software_Developer%E2%80%99s_Guide 

Please let us know which u-boot file should we choose? And we will use it in SPI Flash, how can we download the image file into SPI Flash?

Software: Ubuntu-14.04, ti-processor-sdk-linux-omapl138-lcdk-04.01.00.06 

Hardware: custom board

Thank you,

Luxiye