Different to yor way I always started flashall.bat with the Reach plugged in, at the prompt I unplugged Reach and connected it again after some seconds.
I did this some month ago and don’t recall the LED behaviour and details, but you should get some lines with ‘=>’ telling some actions, the last stuff takes some time, you are asked to wait for something to happen (which never happened in my case) so after 2 minutes I simply unplugged the Reach and plugged it in again and it worked.
I know I did the 1.2 flash with the Intel tool and using the flashall.bat and it worked 90% of the time for me. Flashing 2.3 only worked for me using flashall.bat, but later TB_RTK wrote : https://community.emlid.com/t/unable-to-reflash/5789/6?u=alujoe so maybe it would have worked with the Intel tool as well.
Do you have the problem with one Reach (maybe broken) or with two units ?