Short description of the project (see my other posts): using RP2 and MicroPython with a Waveshare modem on hardware uart.
1) stdio over usb stops when having a lot of communication over the uart (starvation of the TinyUSB task?), partly covered by adding sleep instructions but not sure if that's the way to go (how long should I wait?), irresponsive stdio over usb as result when not putting enough sleep instructions
2) tried to implement the simple "blinking led" on the second core with an easy infinite loop (and a variable to stop it from core 0), stops blinking quite fast (about 5-10 seconds) IRQ problem between USB/UART/TIMER for sleep_ms?
3) tried uasyncio on the second core, stops also quite fast, unless I stop doing my uart stuff on core 0 and just put a sleep instruction one core 0 (what's the point having dual core then

What am I missing? Where did I go wrong? Should I better move to C?