No Console Output from Compiled U-Boot on TWR-VF65GS10 Tower Module

[Rikard1]

I have a pre-built image (Factory Starting Point from LinuxLink Timesys) that includes U-Boot and Linux on an SD card, and it boots successfully with console output via a TWR-SER-SCH and RS232-to-FTDI USB adapter connected to the D9 plug on the board. However, when I compile U-Boot from source (using, for example, the v2025.01 branch on GitHub) and write the resulting U-Boot binary (u-boot.imx) to my SD card with:

sudo dd if=u-boot.imx of=/dev/sdc bs=512 seek=2

I get no output on the COM port, regardless of which U-Boot Git tag I compile. None of the compiled images seem to work.

I’m unsure how to get a compiled U-Boot binary to work with the TWR-VF65GS10 Tower Module so that it outputs to the serial terminal. When using the Factory Starting Point image, power is connected through the OpenSDA USB port (J3), but if I connect power via USB to the secondary elevator, there’s no serial output.

*************************U-boot Compilation ***************************************************

make CROSS_COMPILE=arm-linux-gnueabihf- distclean

make CROSS_COMPILE=arm-linux-gnueabihf- vf610twr_defconfig

make ARCH=arm CROSS_COMPILE=arm-linux-gnueabihf-

[pengyong_zhang]

Hi @Rikard1 

what is your SOC type? Please refer the chapter 4.5.12 How to build U-Boot and Kernel in standalone environment. 

B.R

[Rikard1 · Accepted solution]

Hi Pengyong, u-boot is now working. The issue was that somehow dd did not write to offset 0x400 on my sd card. I do not know what the issue with linux dd is, but i am using a usb hub with sd card input connected to host pc running ubuntu on virtualbox vm. i am using windows dd on host pc and verifying with diskgenius that the u-boot.imx is written to offset 0x400 on the sd card. so far i have verified that i can compile an run u-boot up to v2020.04, but it will not work with v2024 and v2025. This is ok and i will just use the latest version that works on my board.