Can't find crashlog - Get them from RAM?

OpenWRT on TD-W8970 v1 is not stable (at least for what I need). Does not matter which recent version, LEDE 17.01.06, LEDE-snapshot, 18.06, 18.06-snapshot or directly master.... I'm really thinking about rolling back to Chaos Chalmer (there I could use the weirdest config / custom build I could Imagine and always get at least 48hours of uptime)... but I want to at least try to fix thing and get to know what is going wrong...

  • I've tried crack up verbosity and to set up my raspberry as logserver but it didn't work, router crash too hard.
  • I've tried gettin my log back from /sys/kernel/debug/crashlog ( but that file do not exist.
  • Of course I get the message: Crashlog allocated RAM at address 0x3f00000 but I do not know how to manually retrieve it.