Mini USB Portable 3G/4G router - rt5350f - 32M version

Short description how to upgrade router with 32 MB on board.

Source: http://www.ebay.de/itm/400572464175?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1497.l2649

Body:

PCB is exactly the same, only resistor to set mem size to 32m has been added.

Bootloader

Default u-boot bootloader is not fully functional, and it seems that it is protected against starting other firmware than oryginal one.
Do not try to upgrade this bootloader from bootloader menu - you will brick your device  !

To load openwrt firmware new bootloader is needed - I am using - uboot256.img taken from JiapengLi

Openwrt firmware

Default firmware cannot accept openwrt images so at the beggining (after u-boot upgrade) we will load minimal openwrt firmware mini.bin .

Upgrade procedure

Verification

Check twice if it is router we are talking about:

• Take a look on photos of PCB
• Check MDT structure by call "cat /proc/mtd", has to be like below:

cat /proc/mtd

dev: size erasesize name
mtd0: 00400000 00010000 "ALL"
mtd1: 00030000 00010000 "Bootloader"
mtd2: 00010000 00010000 "Config"
mtd3: 00010000 00010000 "Factory"
mtd4: 003b0000 00010000 "Kernel"

          Think twice :)

First step

• Reset router to default settings
• Connect to router via telnet and login with default user name (admin) and password (admin)
• Now  you can upgrade router via FTP or USB

Upgrade via FTP 

• Cceck free memory
• 
  

• Verify free memory by calling free, check if you have more than  3500 free memory 

     

# free     total   used   free  shared buffersMem: 28584  17128  11456     0      0Swap: 0 0 0Total: 28584 17128 11456

•  Resize TMP, and start proftp server

mount -o remount,size=4M tmpfs /tmp
proftpd.sh server 192.168.100.1 192.168.100.1 21 10
proftpd

• Connect to router via ftp and copy uboot256.img and mini.bin to /tmp directory on router
• ! Upgrade uboot - be careful, do not reset router during and after this operation !

mtd_write write  /tmp/uboot256.img Bootloader

• You should see on console 

#Unlocking Bootloader ...
#Writing from /tmp/uboot256.img to Bootloader ...  [w]

• ! Upgrade firmware - do not reset router during this operation!

mtd_write write /tmp/firmware.img Kernel

• You should see on console  

#Unlocking Kernel ...
#Writing from /tmp/mini.bin to Kernel ...  [w]

• Reboot router :), enjoy new u-boot with working ethernet and openwrt firmware. Now you can use standard openwrt upgrade procedure. 

reboot 

• Router will set IP address to 192.168.100.1 , you can login via telnet

Upgrade via USB

• Prepare usb stick, format it with fat filesystem, and copy  uboot256.img and firmware.img 
• Conect usb stick to router and mount it by:

mount /dev/sda1 /mnt

• Wait a few seconds and verify  if you see files

ls /mnt 

• You should see content, do not go further if you do not see files ! 

uboot256.img mini.bin

• ! Upgrade uboot - be careful, do not reset router during and after this operation !

mtd_write write  /mnt/uboot256.img Bootloader

• You should see on console 

#Unlocking Bootloader ...
#Writing from /mnt/uboot256.img to Bootloader ...  [w]

• ! Upgrade firmware - do not reset router during this operation!

mtd_write write /mnt/mini.bin Kernel

• You should see on console  

#Unlocking Kernel ...
#Writing from /mnt/mini.bin to Kernel ...  [w]

• Reboot router :), enjoy new u-boot with working ethernet and openwrt firmware. Now you can use standard openwrt upgrade procedure. 

reboot

• Router will set IP address to 192.168.100.1 , you can login via telnet 

Many Thanks for martin4android for support and materials.