uBoot & Kernel upgrade problem on PogoPlug V4 (no replies)

Original posting here & here

Long story short. uboot was stuck at "Starting kernel ..." after I updated uBoot & Kernel (from 3.14.0 to 4.17.2) Tried to fall back by enter uBoot and load the backed up 3.14.0 uImage & uInitrd gives the same result.

MMC rescan: current device # 0 initialized OK
device mmc 0:1
1 bytes read in 13 ms (0 Bytes/s)
Found bootable drive on mmc 0
loading uImage ...
4125458 bytes read in 131 ms (30 MiB/s)
loading uInitrd ...
6284004 bytes read in 195 ms (30.7 MiB/s)
loading DTB /boot/dts/kirkwood-pogoplug_v4.dtb ...
9962 bytes read in 26 ms (374 KiB/s)
## Booting kernel from Legacy Image at 00800000 ...
   Image Name:   Linux-4.17.2-kirkwood-tld-1
   Created:      2018-08-04   9:08:32 UTC
   Image Type:   ARM Linux Kernel Image (uncompressed)
   Data Size:    4125394 Bytes = 3.9 MiB
   Load Address: 00008000
   Entry Point:  00008000
   Verifying Checksum ... OK
## Loading init Ramdisk from Legacy Image at 01100000 ...
   Image Name:   initramfs-4.17.2-kirkwood-tld-1
   Created:      2018-08-04   9:08:49 UTC
   Image Type:   ARM Linux RAMDisk Image (gzip compressed)
   Data Size:    6283940 Bytes = 6 MiB
   Load Address: 00000000
   Entry Point:  00000000
   Verifying Checksum ... OK
## Flattened Device Tree blob at 01c00000
   Booting using the fdt blob at 0x1c00000


Starting kernel ...

Further testing, from time to time the new uBoot gives "Verifying Checksum ... Bad Data CRC" when loading either uImage or uInitrd when boot. Tested SD card was good (and was the same one I have been using since day 1 in my PogoPlug V4) Is there some changes in uBoot to speed up SD card access?