I know that the boot up log can be obtained by pulling out contents of kmsg or dmesg through ADB. But I\'m not aware of how to retriev
kmsg
dmesg
ADB
Look in some locations such as these:
/proc/last_kmsg /data/tombstones/ /data/dontpanic/ /data/system/dropbox/
(This list isn't strictly kernel logs, including framework and application logs too, which are also sometimes of interest)