Latest firmware of Dragino can be found here.

You can also compile your customized firmware. see HowTo -- Compile firmware for Dragino?

There are several methods to flash the firmware of a Dragino MS12.

Upgrade firmware via Redboot -- for Windows/Linux/MAC

This upgrade method is good to recover the Dragino firmware in a Windows machine. It requires that the Dragino and your computer in the same network.

• Copy openwrt-atheros-vmlinux.lzma and openwrt-atheros-root.squashfs to your tftp server, defautl tftp server set in Redboot is 192.168.255.2. so you would better set your tftp server address to 192.168.255.2 or you have to change the Redboot tftp server ip via ip_addr command.
• Access Redboot via Telnet
• run below commands to flash

RedBoot> fis init
RedBoot> load -r -b %{FREEMEMLO} openwrt-atheros-vmlinux.lzma
RedBoot> fis create -e 0x80041000 -r 0x80041000 vmlinux.bin.l7
RedBoot> load -r -b %{FREEMEMLO} openwrt-atheros-root.squashfs
RedBoot> fis create rootfs
RedBoot> reset

Upgrade firmware via Linux

This upgrade method is good for a remote firmware upgrade.

1. Transfer the .squashfs and .lzma files to the Dragino MS12

[edwin$host ]$ scp bin/openwrt-atheros-vmlinux.lzma root@dragino:/tmp
[edwin$host ]$ scp bin/openwrt-atheros-root.squashfs root@dragino:/tmp

2. look up flash blocks

root@dragino:~# cat /proc/mtd
dev:    size   erasesize  name
mtd0: 00030000 00010000 "RedBoot"
mtd1: 000b0000 00010000 "vmlinux.bin.l7"
mtd2: 00300000 00010000 "rootfs"
mtd3: 000c0000 00010000 "rootfs_data"
mtd4: 0000f000 00010000 "FIS directory"
mtd5: 00001000 00010000 "RedBoot config"
mtd6: 00010000 00010000 "boardconfig"

3. write kernel image:

root@dragino:/tmp# mtd write /tmp/openwrt-atheros-vmlinux.lzma vmlinux.bin.l7

4. write rootfs:

root@dragino:/tmp# mtd write /tmp/openwrt-atheros-root.squashfs rootfs

5. reboot

root@dragino:/tmp# reboot

NOTE when you reflash the rootfs network settings will return to default, e.g. an LAN IP of 192.168.255.1