Sansa e280v2 refurb is NOT a v2.

[simulant]

Just thought I'd put this out there in case  it helps anyone.

I have a Sansa E280v2 refurb.     "e280v2" is printed on the back.

However, if I load  Rockbox (3.51 stable) for the e200v2 series, I get a "codec failure" if I try to play anything.

Rockbox for e200v1 works, however.   Go figure.

[gevaerts]

Just thought I'd put this out there in case  it helps anyone.

I have a Sansa E280v2 refurb.     "e280v2" is printed on the back.

You don't. You have a v1 with bits of the case scavenged from a v2 :) This is actually quite common and well-known, for sansas the writing on the case doesn't mean much.

However, if I load  Rockbox (3.51 stable) for the e200v2 series, I get a "codec failure" if I try to play anything.

Rockbox for e200v1 works, however.   Go figure.

You probably installed the correct (v1) build first a while ago (letting Rockbox Utility autodetect your player so it installed the correct bootloader and build, if I may guess). The main binary of the e200v1 build is .rockbox/rockbox.mi4

After that you installed the e200v2 build, which overwrote most of the files in .rockbox such as codecs and plugins, but it did not overwrite .rockbox/rockbox.mi4, since the v2 main binary is called rockbox.sansa. Due to this the original main binary could still load (the other one wouldn't have worked at all), but the codecs didn't.

Obviously putting back the proper v1 build fixes all this.

[simulant]

Thanks for the clarification.  That's pretty much what happened.