High level, set timer and initiate standby:
enigma2-wetek/Standby.py at 0a6ff15b712d5f94ed4f00a9e9514c59246d999c · openhdf/enigma2-wetek · GitHub
Low level - configs the CPU for standby:
linux-wetek-3.14.y/suspend.h at 9b1e857000d24b66a87ff8bd5a843ac7cbddca6a · wetek-enigma/linux-wetek-3.14.y · GitHub
Won't be available the next two or three weeks, maybe someone else has time to dig into that.
/usr/lib/standby.sh should also be interesting.
I'm using vdr on my wetek and have a similar issue. Tried to use the sd-card (32GB) and ram for timeshift but still have those jumps every couple of minutes.
Of course during the soccer games now it usually happens in the situation when it gets interesting. 
Would that test version from above also work for me, using VDR?
Well, it is a hardware issue. As far as I understand there is no hardware clock to wake the system up at a specific time. Neither is WOL possible.
What should work - and I think emigma is doing just that - to stop all "unnecessary" processes, send a "CEC-standby" message ... and maybe set the LED in front to a specific config (e.g. power: red/blue, LAN and WLAN to yellow).
When the right time comes you "restart" the device - for a first proof of concept a simple reboot would be quick but dirty.
Sufficient for a POV, but would also turn the TV on via CEC. Linux can do better than that.
The right way would be to start all the necessary processes again in time for the recording, but avoid sending a CEC-command to turn the TV on.
If a "switch on command" is received the same sequence to start everything is initiated again, but with the CEC-command. Except if you already have started a recording. In that case you only need to switch the TV on via CEC.
Don't know if it is possible to stop any output to HDMI, while recording (KODI and all necessary drivers are up). Otherwise if somebody (wife, hsuband, kids) switches the TV on, they might be confused.
