I'm having a similar issue. I was able to get my Opta to connect using the 2.0 IDE by manually downloading the zip and copying it into my C:\Users\name\AppData\Local\Arduino15\staging\packages folder. However, I am still unable to get it to connect with the PLC IDE. I cannot figure out how to force the PLC IDE to recognize the opta package. I continue to get the following:
Sketch generated, is changed: true
Error initializing instance: Profile 'opta_1.0.4' not found
Error during build: Platform 'arduino:mbed_opta' not found: platform not installed
I believe that my problem may be with the company firewall. It seems that when I install the PLC IDE tools it is not downloading the gcc-arm-none-eabi-7-2017-q4-major-win32-arduino1.zip file correctly. when I go to C:\Users\name\AppData\Local\T\D\packages I see the zip file there, but it shows 1k file size. I've tried copying the full downloaded version into that location, but I have no idea how to trigger it to install from that location.
I don't have any experience using Arduino PLC IDE, so I don't know what this C:\Users\name\AppData\Local\T\D\packages path is all about. However, you mentioned "2.0 IDE". I can give you some information about Arduino IDE 2.x, which I am quite experienced with.
When you install a boards platform via the Arduino IDE Boards Manager, it checks to see if the installation files are present in a local cache before downloading them from the Internet. If it finds a file in the cache, it uses that local file instead of downloading. So if you have the file, you can avoid the problematic download by the IDE by putting it in that cache. The location of the cache used by Arduino IDE is here:
You should note that gcc-arm-none-eabi-7-2017-q4-major-win32-arduino1.zip is only one of the files Arduino IDE needs to download to install the "Arduino Mbed OS Opta Boards" platform. If try installing the platform via the Arduino IDE Boards Manager and have problem with other files, I can provide you with the download URLs of those other files if needed.
ptillisch: Thank you for your interest in my post. I appreciate that you are trying to help me, but it seems that you did not read my post. I am aware of the mechanics of the board installer in the 2.x IDE and scited the same path you did in your own post when I said that I used it to get the 2.x IDE to install my OPTA board. I am only experiencing problems with the PLC IDE. After spending 5 hours trying various things I am no closer to getting it to work on my computer it seems. Again I appreciate that you took the time to try to help, but I am looking for expertise on the PLC IDE not the 2.x IDE.
I managed to solve my issue. I had to install on another computer, then I copied the folder structure from the successful install over to the computer that was having issues. Specifically I copied the files and folders from: C:\Users\name\AppData\Local\T
Note: you may want to exlude the arduino-cli.yaml file and keep the original as it has the working directory paths which may be different between the two computers.
But after some research it turns out that the thing that was causing all the trouble for me was the sketch.yaml file located in the Local\T directory. It was missing 2 sections that the successful install had.