Here's a video: http://youtu.be/jUMIhA_mKE4
I had to downgrade my hboot from 1.56 to 1.44 to get S-ON, I suppose I should upgrade it to the latest version so it matches everything else?
I followed this guide: http://www.htc1guru.com/guides/return-stock-guide/
that video show's correct (stock) bootup and powerdown animations, but a (possibly) modded bootsplash.... that would be partition mmcblk0p13 and can't be flashed without S-Off
though an RUU should have taken care of that!!
PS: I say possibly, because maybe your version (HTC__621) is supposed to be like that.
doesn't matter if it was a ruu.zip or ruu.exe both would/should change the bootsplash... can you check the zip if it has "splash1.nb0" that would be the bootsplash.
ruu (zip or exe) contain everything so hboot and bootsplash should already by stock.
maybe it's just supposed to be that way for you??