Bangle.js2: Bootloader now 'Hold BTN to reboot' not 'BTN1 = REBOOT'/etc

For BJS1 we didn't have much flash, but compiler/code has improved now and BJS2 has more anyway

ChangeLog

@@ -45,6 +45,7 @@
             Bangle.js: Add Bangle.setOptions({manualWatchdog:true}) to enable users to supply their own JS watchdog
             Bangle.js2: DFU update from flash now retries if CRC doesn't match
             Bangle.js2: Bootloader now shows 'Hold button to turn on' to avoid users assuming it is dead when it's not
+            Bangle.js2: Bootloader now 'Hold BTN to reboot' not 'BTN1 = REBOOT'/etc
 
      2v24 : Bangle.js2: Add 'Bangle.touchRd()', 'Bangle.touchWr()'
             Bangle.js2: After Bangle.showTestScreen, put Bangle.js into a hard off state (not soft off)

targets/nrf5x_dfu/main.c

@@ -159,7 +159,7 @@ bool dfu_enter_check(void) {
 #if defined(BUTTONPRESS_TO_REBOOT_BOOTLOADER) && defined(BTN2_PININDEX)
       lcd_print("RELEASE BTN1 FOR DFU\r\nBTN1 TO BOOT\r\nBTN1 + BTN2 TURN OFF\r\n\r\n<                   >\r");
 #else
-      lcd_print("RELEASE BTN1 FOR DFU\r\nBTN1 TO BOOT\r\n\r\n<                   >\r");
+      lcd_print("RELEASE BTN FOR DFU\r\nHOLD BTN TO BOOT\r\n\r\n<                   >\r");
 #endif
       lcd_flip();
 #ifdef BTN1_PININDEX
@@ -198,7 +198,7 @@ bool dfu_enter_check(void) {
       } else {
         lcd_clear();
         print_fw_version();
-        lcd_println("DFU START");
+        lcd_println("DFU STARTED");
       }
       set_led_state(true, true);
     }
@@ -279,7 +279,11 @@ void dfu_evt_init() {
       NULL); // context
 #endif
 #ifdef BUTTONPRESS_TO_REBOOT_BOOTLOADER
+#ifdef BTN2_PININDEX
   lcd_println("BTN1 = REBOOT");
+#else
+  lcd_println("\nHOLD BTN TO REBOOT");
+#endif
 #endif
 }
 
@@ -352,7 +356,7 @@ int main(void)
 
 #ifdef BANGLEJS_Q3
     lcd_init();
-    lcd_println("\n  HOLD BUTTON\r\n  TO TURN ON");
+    lcd_println("\n  HOLD BUTTON 2 SEC\r\n  TO TURN ON");
 #endif
 
     // Did we just power on? If not (we watchdog/softreset) RESETREAS will be nonzero