Error starting Arduino IDE: https://downloads.arduino.cc/packages/package_index.

I am trying to install the Arduino ide on my raspberry pi 3. Downloaded the ARM32 package, untarred and installed it. When starting the ide I get the message: "https://downloads.arduino.cc/packages/package_index.json". I need this file for my MKR1000 board. I installed the Arduino ide on ubuntu yesterday (for an x86 system) and that worked flawless.

The error message from Java is very long. I can copy it if needed in but it ends with:
Error downloading https://downloads.arduino.cc/packages/package_index.json
2020-02-12T20:48:03.326Z INFO c.a.c.p.ContributionInstaller:314 [ContributionManager Update Thread] Downloaded package index URL=[https://downloads.arduino.cc/packages/package_index.json]
2020-02-12T20:48:03.335Z INFO c.a.c.p.ContributionInstaller:324 [ContributionManager Update Thread] Check unknown files. Additional package index folder files=[package_index.json], Additional package index url downloaded=[]

I am not aware of unknown files. I found this package at the designated URL. I can download it by hand if necessary but than I still don't know where to install it.

Anybody any idea?

This is a known bug with the Linux ARM version of Arduino IDE 1.8.11:

Please use Arduino IDE 1.8.10 until Arduino IDE 1.8.12 comes out with the bug fixed. You can download Arduino IDE 1.8.10 here:

Thanks! I now have version 1.8.10 installed. Alas this version has its own problems. When I try to compile the Blink example I get the error that libfl.so.2 does not exist. I installed and updated the recommended libraries and boards, removed and reinstalled the SAMD library, rebooted each time but the error persists. What did I do wrong? The exact message is:

/home/arnold/.arduino15/packages/arduino/tools/arm-none-eabi-gcc/7-2017q4/bin/arm-none-eabi-ar: error while loading shared libraries: libfl.so.2: cannot open shared object file: No such file or directory
exit status 127
Error compiling for board Arduino MKR1000.

I could not include the verbose compiler output because the message is too long.

Raspberry 3B
Raspbian version 10
Kernel version 4.19.93-v7+
Arduino: 1.8.10 (Linux), Board: "Arduino MKR1000"

FYI, Arduino IDE 1.8.12 was just released a few hours ago, and it should have the original bug you reported fixed.

But using Arduino IDE 1.8.12 won't fix this new error. I think the solution to that error is described starting here:

Yes, this did the trick! I'd forgotten to mention that I had tried to apt install libfl.so.2 (which of course didn't work) so I was happy with your suggestion. 1.8.10 worked ok. Next I installed 1.8.12 and that worked immediately (libfl2 was already installed). The blink sketch now works out of the box from Raspberry to MKR1000.

Thanks for your help!

You're welcome. I'm glad to hear it's working now. Enjoy!
Per