Delete firmware update files

[C4thie]

Before I put airplane mode, my Kindle already downloaded some update file and I would like to delete it. Once I decide to update, I'll do it manually.
I've got few questions:

1) Is it safe to delete update files? Without causing system instability or something

2) How to find all update files? Where they are stored?

[j.p.s]

1) Yes, it is safe to delete.

2) A partially downloaded file is name update.bin.tmp.partial and it is located in the root of the directory exported over USB to your computer. (The documents directory with your books is also in that root directory.) Immediately after update download is complete update.bin.tmp.partial will get renamed to Update_something_or_other.bin and the kindle will immediately start to update. When the update is complete the Update_something_or_other.bin file will be updated deleted.