[Galaxy S6 Edge General] Eudemony:
It seems Samsung in it's infinite wisdom decided it will make the boot sound on Marshmallow silent.

I've seen this on Note 5, S6, S6 Edge, S6 Edge+, S7 and S7 Edge Marshmallow stock roms

When you extract the system.tar from these Marshmellow roms the audio file for PowerOn.ogg is silent.

So, if you want a boot sound you need

1. Root and / or custom recovery - like TWRP

2. a new PowerOn.ogg (or an old one from a previous rom if that is what you like)

3. a root file manager / browser app (I use root explorer v3.3.7 as v4 seems to have bugs?!?)

Q: Where is the boot sound located?

A: root/system/media/audio/ui -> PowerOn.ogg

In this screenshot you can see I have already replaced PowerOn.ogg due to the larger file size and date

I am using the PowerOn.ogg from my Note 4 running android 5.1.1

You can download it from my google drive here -> https://drive.google.com/file/d/0BxOh5UkYXJw0NzZKSG9FU0NNTVU/view

(click the downward pointing arrow up the top to download the file when you are on the page)

best to use your phone to download this for this tutorial as I will reference the place it is download to (by default) or you can manually put it here from your PC

The location the file saves to is sdcard/Download -> PowerOn.ogg

Q: How do I change this manually on my phone

Well, you need root (to access and re-write system files) and a root browser app (there are free ones I believe on google play but I use "root explorer" as outlined above as this was a free paid app from amazon a while ago!)

So this is my guide (with pictures) using root explorer but the same applies with any root browser app

1. Install "root explorer" from Google Play (or any free alternative) - https://play.google.com/store/apps/details?id=com.speedsoftware.rootexplorer&hl=en

2. Open "root explorer" from your app drawer or from the google play app (if you just downloaded it)

3. Once in root explorer navigate to where you saved the downloaded PowerOn.ogg on your phone (sdcard/Download)

4. Long press on the file PowerOn.ogg and an options menu will pop up, then select "Copy"

5. You will now see down the bottom of the app an option for COPY HERE

6. Scroll up on the root explorer listing and press ".. " (parent folder) until the folder is back to "ROOT"

7. Then navigate to system/media/audio/ui

8. Press COPY HERE which is located on the bottom left

9. You will get a warning that the folder is read only - press Yes

10 You will get a warning that PowerOn.ogg already exists and do you want to over write it - press Yes

The new PowerOn.ogg is now written to your system

11. We now have to change permissions of the file to match those in the folder (currently the file is rw-rw-rw and we want it rw-r--r--

12. Long press on the file PowerOn.ogg and an options menu will pop up - Select Properties

13. Change the properties to Owner - Read and Write, Group - read, Others - read by un-ticking the boxes in the write column on the rows of Group and Others and then select OK

14. Check the read write properties is the same as the other files

15. Exit out of the app (press home button) then turn up your system volume!

... and reboot and enjoy!!!