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T-Com Speedport W921V

Board: Arcadyan VGV953


Hardware Info

Architecture MIPS
Vendor Lantiq
bootloader U-Boot
System-On-Chip VR9 VRX 288 (MIPS 34K V5.5)
CPU/Speed 34K V5.5 500 MHz
Flash-Chip NAND256W3A
Flash size 32 MiB NAND Flash
Ram-Chip W971GG6JB-25
RAM 128 MiB
Wireless-2,4 XWAY WAVE300 - PSB 8304 V V1.1
Wireless-5 XWAY WAVE300 - PSB 8301 V V1.1
Dect COSIC Modem PMB 9643V V2.0
Modem XWAY VRX208 PSB 80190 V V1.1
Ethernet XWAY PEF 42068 F swconfig
Isdn PSB 21150 F V1.4
USB Yes 2 x 2.0
Serial Yes

Replacement of factory U-Boot

Power off board.

Short the (R133) and power on the router. Add picture of location, there is no resistor, just pads, next to the shield in the middle.

When CFG 04 UART Popups in terminal You can disconnect/revert R133 short to normal or You can wait till the end of process.

ROM VER: 1.0.5                                                                  
CFG 04                                                                          
EEPROM Data OK                                                                  

Upload a special (uboot-vgv953.asc) U-Boot RAM image using a serial (baud 115200) cable via „Send File”(terraterm for win or cutecom for linux).

Wait for U-Boot to load and stop auto-boot process.


Step 1: Type in console

nand erase.chip

Step 2: Set Your IP addres to “” and start tftp server

Step 3: Place uboot-vgv953.bin in tftp folder

Step 4: Type in console

tftp uboot-vgv953.bin

Step 5: Type in console

nand write 81000000 0 0x{filesize in hex}

Step 6: Reset board

Installing OpenWrt

Step 1: Stop U-boot auto boot process and modify to auto boot OpenWrt at power on

setenv nboot 'nand read 0x80800000 0x60000 0x200000; bootm 0x80800000'
setenv bootcmd 'run nboot'

Step 2: Erase NAND

nand erase 0x60000 0x1fa0000

Step 3: Set Your IP addres to “” and start tftp server

Step 4: Place openwrt-lantiq-xrx200-VGV953-ramfs image in tftp folder

Step 5: Upload initramfs image

tftp openwrt-lantiq-xrx200-VGV953-ramfs

Step 6: Run initramfs image and wait till fully booted


Step 7: Wait until boot complet, then upgrade via web with this openwrt-lantiq-xrx200-VGV953-ubifs-sysupgrade

Hint: Ram Image or uncompressed Kernel should be smaller than 4.2 MB or boot will fail with “Uncompressing Kernel Image … LZMA: uncompress or overwrite error 7 - must RESET” u-boot limitation post links to 18.06.0 initramfs and sysupgrade, Git for master UBIFS recovery on boot message keeps me from pushing it to openwrt currently 18.06.0 files will follow


There are some problems with device.

wifi not working (no drivers for lantiq wave)


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toh/t-com/spw921v.txt · Last modified: 2019/10/16 10:33 by tmomas