I have an iPhone 6, from back in the days when phones had headphone jacks.
I can load Basic programs from the Bally Alley archives using my iPhone connected to the Cassette jack built into the Astro Basic cartridge. No problems there.
I can also save custom Basic programs by running the cassette line into the MIC input on the back of my desktop Windows PC. Again, easy peasy.
What I can't figure out is how to get my iPhone to record custom Basic programs directly. I've tried buying splitters that separate the MIC and Headphone pins into separate jacks, but no matter what I do every audio recording app I've tried just records the room noise using the phone's built-in microphone instead of the line plugged into the jack. Has anyone figured out a rig that can save Astro Basic programs directly to an iPhone?