Hello Niladridm,
I opened a ticket on this forum and WP Series forum about SD card problems (not quite the same problem).
https://forum.sierrawireless.com/viewtopic.php?f=178&t=9885&sid=2e9a4ce0ef47d18dbeae25a5a1d5e2f9
I am pleased to see that the next version (version 12) may solve problems because my post went unanswered.
For SD card detection with release 11:
load driver:
insmod /lib/modules/3.14.29ltsi-c14b887744_39dcf2256d/kernel/drivers/mmc/host/msm_sdcc.ko
Mount device (example)
mkdir -p /mnt/userrw/sdcard
/bin/mount -t auto -o sync /dev/mmcblk0p1 “/mnt/userrw/sdcard”
Thanks