using a Heltec WiFi32 LoRa V4 Arduino IDE 2.3.10 ESP32 core 3.3.10
testing File>Examples>Heltec_ESP32_Dev-Boards\examples>LoRaBasic>DeepSleepWakeUpByLora
Tools>Board selected Heltec WIfi LoRa (V4)
Tools >Board selected LoRa FEM Type: USE_KCT8103L_PA.
if I build with USB CDC on Boot: Enabled I get a link time error undefined reference to `HWCDCSerial’, full message
C:/Users/xxx/AppData/Local/Arduino15/packages/esp32/tools/esp-x32/2601/bin/../lib/gcc/xtensa-esp-elf/14.2.0/../../../../xtensa-esp-elf/bin/ld.exe: C:\Users\drbri\AppData\Local\arduino\sketches\5D498CFE55A744FD43A40CA5BA4D4244\sketch\DeepSleepWakeUpByLora_V3.ino.cpp.o:(.literal._Z8OnRxDonePhtsa+0x10): undefined reference to `HWCDCSerial'
collect2.exe: error: ld returned 1 exit status
if I build with USB CDC on Boot: Disabled it compiles, links, uploads and runs OK
however I have to use U0TXD for serial output
EDIT: if I build with
Tools >Board LoRa FEM Type: USE_NONE_PA (default)
Tools>Board USB CDC on Boot: Enabled*
it compiles, links, uploads and runs OK and serial output is over the USB