Now I am using same uboot.img and uEnv.txt and just replacing dtb and uImage for 4.4
U-Boot SPL 2016.07 (Jul 19 2016 - 00:02:40)
Trying to boot from MMC1
MMC partition switch failed
*** Warning - MMC partition switch failed, using default environment
reading u-boot.img
reading u-boot.img
U-Boot 2016.07 (Jul 19 2016 - 00:02:40 +0530)
Watchdog enabled
I2C: ready
DRAM: 512 MiB
MMC: OMAP SD/MMC: 0, OMAP SD/MMC: 1
*** Warning - bad CRC, using default environment
Net: <ethaddr> not set. Validating first E-fuse MAC
cpsw, usb_ether
Press SPACE to abort autoboot in 2 seconds
switch to partitions #0, OK
mmc0 is current device
Scanning mmc 0:1...
switch to partitions #0, OK
mmc0 is current device
SD/MMC found on device 0
switch to partitions #0, OK
mmc0 is current device
SD/MMC found on device 0
reading boot.scr
** Unable to read file boot.scr **
reading uEnv.txt
351 bytes read in 3 ms (114.3 KiB/s)
Loaded env from uEnv.txt
Importing environment from mmc0 ...
Running uenvcmd ...
Booting from Network ...
reading uImage
8715288 bytes read in 493 ms (16.9 MiB/s)
reading am335x-boneblack.dtb
56891 bytes read in 9 ms (6 MiB/s)
## Booting kernel from Legacy Image at 82000000 ...
Image Name: Linux-4.4.90
Created: 2017-10-07 15:26:28 UTC
Image Type: ARM Linux Kernel Image (uncompressed)
Data Size: 8715224 Bytes = 8.3 MiB
Load Address: 80008000
Entry Point: 80008000
Verifying Checksum ... OK
## Flattened Device Tree blob at 88000000
Booting using the fdt blob at 0x88000000
Loading Kernel Image ... OK
Loading Device Tree to 8ffef000, end 8ffffe3a ... OK
Starting kernel ...
I am booting with SD card.