Serial comm UART1 works on Arduino but makes ESP32 continuously reboot

Question

This comm sketch simply read incoming bytes from the UART 1 where a device is attached. It works normally on a real Arduino device. But on ESP32, it makes it continuously reboot with the following messages:

([UPDATE] Note that there is no reboot on ESP32 is I use Serial2 instead of Serial1)

9:13:19.676 -> ets Jun  8 2016 00:22:57
19:13:19.676 -> 
19:13:19.676 -> rst:0xc (SW_CPU_RESET),boot:0x13 (SPI_FAST_FLASH_BOOT)
19:13:19.676 -> configsip: 0, SPIWP:0xee
19:13:19.676 -> clk_drv:0x00,q_drv:0x00,d_drv:0x00,cs0_drv:0x00,hd_drv:0x00,wp_drv:0x00
19:13:19.676 -> mode:DIO, clock div:1
19:13:19.676 -> load:0x3fff0018,len:4
19:13:19.676 -> load:0x3fff001c,len:1216
19:13:19.714 -> ho 0 tail 12 room 4
19:13:19.714 -> load:0x40078000,len:10944
19:13:19.714 -> load:0x40080400,len:6388
19:13:19.714 -> entry 0x400806b4
19:13:19.786 -> Yo! from serial UART 18/19
19:13:19.786 -> SbmDi⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮@D@⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮⸮
@%cGuru Meditation Error: Core  1 panic'ed (IllegalInstruction). Exception was unhandled.
19:13:19.823 -> Memory dump at 0x400e90f4: ffffffff ffffffff ffffffff
19:13:19.823 -> Core 1 register dump:
19:13:19.823 -> PC      : 0x400e90f8  PS      : 0x00060530  A0      : 0x800d1529  A1      : 0x3ffb1f80  
19:13:19.823 -> A2      : 0x3ffbfe88  A3      : 0x3ffbfe6c  A4      : 0x0001c200  A5      : 0x0800001c  
19:13:19.823 -> A6      : 0x00004e20  A7      : 0x00000000  A8      : 0x800d0c4f  A9      : 0x3ffb1f60  
19:13:19.857 -> A10     : 0x3ffbfe6c  A11     : 0x3f40013b  A12     : 0x0800001c  A13     : 0x00000009  
19:13:19.857 -> A14     : 0x00000009  A15     : 0x00000000  SAR     : 0x00000016  EXCCAUSE: 0x00000000  
19:13:19.857 -> EXCVADDR: 0x00000000  LBEG    : 0x400014fd  LEND    : 0x4000150d  LCOUNT  : 0xffffffbd  
19:13:19.857 -> 
19:13:19.857 -> ELF file SHA256: 0000000000000000
19:13:19.857 -> 
19:13:19.857 -> Backtrace: 0x400e90f8:0x3ffb1f80 0x400d1526:0x3ffb1fb0 0x400860ed:0x3ffb1fd0
19:13:19.891 -> 
19:13:19.891 -> Rebooting...

Here's my code:

#include <Arduino.h>

#define SbmDisplaySerial Serial1

void setup() {
  Serial.begin(115200);
  //Serial.setDebugOutput(true);
  Serial.println("Yo v0.0.1! from serial UART 18/19");

  SbmDisplaySerial.begin(9600, SERIAL_8N1);//, 16, 17);


  Serial.print("SbmDisplaySerial is ");
  Serial.println(SbmDisplaySerial);
}

int _loop = 1;

void loop() {
  // put your main code here, to run repeatedly:
  Serial.print("Loop #"); Serial.println(_loop++);
  delay(1000);

  if (!SbmDisplaySerial.available()) {
    delay(2000);
    Serial.println("No byte avail from the UART, looping…");
    return;
  }


   int b = 0;

   Serial.print("Synching with message limit (waiting for 0xA5 (165) header byte): ");
   int i=0;
   do {
     delay(10);
     b = SbmDisplaySerial.read();
     Serial.print(b);  
     Serial.print(" ");
     if (i%128==0) Serial.println();  
      i++;
   }
   while(b!=0xa5);

  Serial.println("Ok, packet started!");
  Serial.print("Received bytes: ");
  Serial.print(b);
  Serial.print(" ");

  int soc = 0;
  int voltage = 0;
  int current = 0;
  int capacity = 0;

  for(int i=1; i<16; i++) {   
    b = SbmDisplaySerial.read()&0xff;

    Serial.print(b);
    Serial.print(" ");

    switch(i) {
      case  0: Serial.print("Header byte 0xA5"); 
        voltage = 0;
        current = 0;
        capacity = 0;
      break;
      case  1: soc = b; Serial.print("(SoC: ");  Serial.print(soc); Serial.print("%) "); break;
      
      case  2: voltage = b<<8; break;
      case  3: voltage |= b;  Serial.print("(");  Serial.print(float(voltage)*0.01); Serial.print("V) "); break;
      
      case  4: capacity = b<<24; break;
      case  5: capacity = b<<16; break;
      case  6: capacity = b<<8; break;
      case  7: capacity |= b;  Serial.print("(");  Serial.print(float(capacity)*0.001); Serial.print("A.h) "); break;
      
      case  8: current = b<<24; break;
      case  9: current = b<<16; break;
      case 10: current = b<<8; break;
      case 11: current |= b;  Serial.print("(");  Serial.print(float(current)*0.001); Serial.print("A) "); break;
      
      //case 12: current = b<<8; break;
      //case 13: current = b<<8; break;
      //case 10: current |= b;  Serial.print("(TOA: ");  Serial.print(float(current)*0.001); Serial.print("Seconds) "); break;
    }
    

    if (!SbmDisplaySerial.available()){
      delay(2000);
      Serial.print(" No more byte prior reaching 16 bytes, looping…");

      break;
    }
  }

  Serial.println("Waiting for next packet");
  delay(10000);
  
}

[UPDATE] When ran on Arduino, I get typical logs as follows:

11:20:18.217 -> Yo v0.0.1! from serial UART 18/19
11:20:18.217 -> SbmDisplaySerial is 1
11:20:18.217 -> Loop #1
11:20:19.204 -> Synching with message limit (waiting for 0xA5 (165) header byte): 0 
11:20:19.204 -> 0 0 0 0 165 Ok, packet started!
11:20:19.275 -> Received bytes: 165 28 (SoC: 28%) 4 251 (12.75V) 0 0 54 248 (14.07A.h) 255 255 0 0 (0.00A) 0 0 0 0 Waiting for next packet
11:20:29.263 -> Loop #2
11:20:30.266 -> Synching with message limit (waiting for 0xA5 (165) header byte): 0 
11:20:30.266 -> 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 165 Ok, packet started!
11:20:30.508 -> Received bytes: 165 28 (SoC: 28%) 4 251 (12.75V) 0 0 182 0 (46.59A.h) 0 0 0 0 (0.00A) 0 0 0 0 Waiting for next packet

Answer 1

Here is what I've ended up with: I dropped Serial1 as I did not find anyway to make it run and I switched to Serial2, where everything works as expected.

Answer 2

#define SER1_RX 35
#define SER1_TX 32

void setup()
{   
    Serial.begin(115200);                       // 
    Serial.setDebugOutput(1);

    // For Serial1, be sure to set the communication port.
    Serial1.begin(115200, SER1_RX, SER1_TX);    // set the communication port
}