Xiao ESP32-c3, A fatal error occurred: No serial data received

[Hossifer]

I'm using a Xiao esp32-c3. Yesterday, I was trying to get a function to run on one of its cores with the bulk or the program running on the other, at which point I noticed it was acting a little weird, returning indexes from an array that were numerically close to the indexes of the array, but weren't part of it (there were indexes 0-16 in the array, and it was returning 19, and 20, etc.), which it didn't do until I tried to run the "matching" function on core 0. Today, I've been unable to upload anything, getting: A fatal error occurred: No serial data received., upon trying to upload. I basically followed an online example to get that far, so I don't think I could have permanently fried anything just with a programming error, but I'm wondering, what is the fix for this? Something to reset hardware wise?

Thanks

Here's the full error message:

esptool.py v4.2.1
Serial port COM5
Connecting...
Chip is ESP32-C3 (revision 3)
Features: Wi-Fi
Crystal is 40MHz
MAC: a0:76:4e:44:f9:ec
Uploading stub...
Running stub...
Stub running...
Changing baud rate to 512000

A fatal error occurred: No serial data received.
A fatal error occurred: No serial data received.

[Hossifer]

With verbose debug, I get:

esptool.py v4.2.1
Serial port COM5
Connecting...Traceback (most recent call last):

File "esptool.py", line 34, in
Chip is ESP32-C3 (revision 3)
File "esptool_init_.py", line 1004, in main
Features: Wi-Fi
File "esptool_init.py", line 790, in main
Crystal is 40MHz
File "esptool\loader.py", line 1108, in flash_set_parameters
MAC: a0:76:4e:44:f9:ec
File "esptool\loader.py", line 406, in check_command
Uploading stub...
File "esptool\loader.py", line 375, in command
Running stub...
File "esptool\loader.py", line 307, in read
Stub running...
StopIteration
Configuring flash size...
[6252] Failed to execute script 'esptool' due to unhandled exception!
An error occurred while uploading the sketch

[J-M-L]

Can you share the code?