Confirmed that was it.
I worked around it in a way that would still work on official boards, and would also help if an RTC failed:
===================================================================
--- main.cpp (revision 798d2fea340b9bccdb317a7bac285a5d3c31d33a)
+++ main.cpp (date 1586518946000)
@@ -297,9 +297,14 @@
pd.init(); // ProgramData init
- setSyncInterval(RTC_SYNC_INTERVAL); // RTC sync interval
- // if rtc exists, sets it as time sync source
- setSyncProvider(RTC.get);
+ if (RTC.detect()) {
+ setSyncInterval(RTC_SYNC_INTERVAL); // RTC sync interval
+ // if rtc exists, sets it as time sync source
+ setSyncProvider(RTC.get);
+ }
+ // else no RTC: relying on NTP and for the clock to be somewhat accurate.
+ // May need to reduce NTP interval if the drift is bad
+
os.lcd_print_time(os.now_tz()); // display time to LCD
os.powerup_lasttime = os.now_tz();
Happy to make a PR if that’s appropriate.
Many thanks for the guidance.