From your description, You are trying to download firmware image to the FX3 SuperSpeed Explorer kit. From the snapshot, I think you need to do the following things to locate the issue.
1. Could you please check if your fx3_sdk_linux is the latest one(You could download the lastest one from link: EZ-USB FX3 Software Development Kit | Cypress Semiconductor ). From the "Succesfully downloaded" dialog, seems the firmware image has been downloaded succesfully from start button click hanlder-on_pb4_start_clicked, then API fx3_usbboot_download has correct return. Could you check with lsusb to see if you could find the relevant devices after you download the firmware image.
2. From application prints "Failed to stat file\n Error: Invalid firmware file format", check from the source code, we could prints additional files name. From your console prints without filesname, it seems some mismatch. Please check with the tips 1 lastest SDK in linux.
First, thank you for your reply.
I installed the latest version of fx3_sdk_linux, but I do not know what 'start button click hanlder-on_pb4_start_clicked' you were talking about. Where is the button?
Regarding the error code, I will check the file name again.
Thanks for the tip.
Thanks a lot !!