FIXED: refreh-/deepsleep problem with d1 mini + 1.54bw eink

Hi all
I am working on a small infoscreen with weather, garbage-collection and bus-information.

I am using the following hardware components
Wemos D1 min
TZT 1.54b/w epaper from AliExpress
DS3231 RTC

In order to control the screen, i use ZinggJM's wonderful GxEPD-Library (many thanks @ZinggJM!). All is working quite well, but now i wanted to make the last step and work on power-reduction (this should be running of a battery).
I connected the RTCs SQW-Pin with a capacitor to RST in order to use the two alarms provided by the RTC. It works every second time, but every other time, only the time (and strangely bus-times) are displayed, everything else (symbols, weather etc) is gone.

I googled a lot and found two things:

  • Someone (unfortuanetly i can't find the entry anymore) on the forum who has similar problems and got the hint from ZinggJM to use EPD2. I tried, but this was working even less. Maybe because i can't connect my BUSY to the display, if i do the RTC stops working
  • Someone told me to get rid of the alarms and use the ESPs internal RTC to wake it up (D0-RST). But this seems to be exactly the same issue.

I really have no idea anymore. Could maybe someone help me with that? As you maybe found out i'm quite new to this, in fact it's my first project with arduino...

Here is my Repo: GitHub - mr-deamon/infoscreen

after a lot of tinkering, i found the solution (but don't ask my why it's working this way):

after the very first start of the code, do not run display.update() but display.updateWindow(0,0,200,200).

I don't know why this first run defines the working of the following runs, but it seems to be working!