Hi @efimius. Thanks for taking the time to post an update with your findings!
Which version of Arduino IDE are you using? I ask because, as you found, it is true that older versions of Arduino IDE 2.x required you to use "Upload Using Programmer" when uploading via an ISP programmer. However, since version 2.3.3, it should be possible to upload to the ATtiny2313 while you have Tools > Board > ATTinyCore > ATtiny2313(a)/4313 (No bootloader) selected from the Arduino IDE menus by simply clicking the "Upload" button on the IDE's toolbar (or selecting Sketch > Upload from the menus):
Support "Upload Using Programmer by default" feature
arduino/arduino-ide#2500,arduino/arduino-ide#103Arduino IDE offers two methods for uploading sketches to a board:
- "Upload": Upload directly via the board's interface to the computer.
- "Upload Using Programmer": Upload via the ISP programmer that is selected from the Tools > Programmer menu
Some boards don't have the capability to be uploaded to via a direct interface to the computer, so it is always necessary to use an ISP programmer to upload to these boards. In order to make the use of these boards more convenient, the Arduino boards platform framework allows the board definition to be configured so that when the user triggers an "Upload", an "Upload Using Programmer" is instead triggered.
Previously, Arduino IDE 2.x did not support this "Upload Using Programmer by default" feature, meaning that an "Upload" operation would fail with an "
A programmer is required to upload" error. Support for the feature has now been added.