Downloads show up, but then "No such file or directory"
System: Debian jessie on HP 8770w.
I'm sure I'm missing something completely obvious here, but I can't figure out what it is. I downloaded a .img file (TWRP, to modify a phone) and its .md5, to check it. But when I try to do anything with either of those, it says "no such file or directory." I can't md5sum it, I can't install the .img on the phone with adb, I can't do anything.
I searched for info, but it seems like most people reporting things showing up but not being usable were struggling with executables, and it was an issue related to using 32bit executables on a 64bit machine.
Another site suggested it could be infected with a rootkit. I would have been surprised, but checked with Lynis and chkrootkit anyway. There was one positive on chkrootkit, but it sounds like it was a false positive since it's been reported that way elsewhere and Lynis wasn't worried.
What am I doing wrong here?
Thanks in advance!