Still same trouble with mine. Using ecuflash 1.29 I get:
[13:32:46.535] denso02_bootloader_cmd_start
[13:32:47.768] denso02_bootloader_cmd_start
[13:32:49.000] denso02_bootloader_cmd_start
[13:32:50.232] denso02_bootloader_cmd_start
[13:32:51.465] denso02_bootloader_cmd_start
[13:32:51.886] kernel get version
...then an error message pop-up.
Ecuflash 1.42 doesn't recognize the interface cable at all. Seems like a good chap, but I'd love to see this writeup from a client of his.