Thanks: This would not have been possible without the wonderful work of rayman86 for his blobtools, whirleyes for his splash patcher, and gee one for putting up with my total noob questions while I stumbled through this :3
The usual Disclaimer applies here, I'm not responsible for bricks, and if you're trying this with Sbkv2 (Like I did) and mess up, quite frankly you are FOUBAR SOL OCSA!! Be.. Careful. May the force be with you.
This guide was run on a Windows 7 (x64) machine, I was going to use linux, but I couldn't get Blobtools source to compile into something working (since I'm functionally retarted), the commands are pretty much exactly the same though, if you can get blobtools working.
1. The latest ASUS update firmware from their site for your region: (I used US .24 firmware) link
2. Rayman84's (Give him thanks!) Blobtools (don't need boottools for just a splash screen change) [Attached] Original thread: link
3. A hex editor, I used xvi32 (you just need to be able to read and compare blobs) link
4. Three Images that you want to patch the splash screen with, the sizes need to be exactly 300x100 (asus logo) 300x90 (below) and 300x30 (Nvidia logo)
Note: Due to the nature of how the image is stored (In the freaking bootloader I might add -_-) these sizes need to be Correct, the bootsplash patcher should help you with this.
5. whirleye's (Give him thanks!) Boot Splash Patcher windows app. (Complete with shiny GUI) link
6. 3 pinches of ground unicorn horn, eye of newt, and hog's blood (extremely important ! ) Link
*Make yourself a mental note of the disorganized location of these files as you scatter them throughout your documents/desktop/downloads folders.*
1. Unzip the asus update, inside it is another zip, which you unzip. (Okay ASUS, you likes your zips) Inside there is a blob file, don't be alarmed, it will not attempt to absorb you into it's blobbiness, it stands for a Binary Large OBject file.
2. Put blobunpack into the same directory as the blob. (for easy cmd command)
3. MOD4+R (Windows key+R) to open run box, type 'cmd' This doesn't stand for central machine decimator.
4. Navigate to the directory with your blob, it was getting pretty lonely without you anyway. Ex: cd C:/users/username/downloads/blob
5. type blobunpack blob, your blob will now split itself into a multitude of blobs each with its own suffix. You now have to say Blob sr. and blob jr. when addressing them, it's only proper.
5a. You will (should) get:
blob.header (Oddly, I didn't actually get this, but we don't need it so don't worry about it.)
blob.app (huge file, the actual update system.img) [Don't Need]
blob.ebt (bootloader) [Need this blob]
blob.lnx (boot.img) [Don't Need]
blob.sos (recovery) [Avoid like the plague, unless you like losing cwm :3]
Note: The file extentions are 'false', they're just a way of separating the blob into manageable sections, they're all just blobs topped with a fancy-schmancy file extension.
6. Now that the blob has lost some extra poundage, it's time to patch it, Backup the blob.ebt and open the blob.ebt with whirleye's patcher!
7. Use your keyboard (This be old school) to load the images into the blob.ebt, shortcuts are at bottom and the tool is easy to use.
8. Save as patched_bl.bin, this should enable save as blob. (I had to do this for whatever reason, just don't question the gods)
At this point, you *Should* have a ready to patch bootloader with your new fancy image! If you like having a device that doesn't double as a very fancy paperweight, you'll keep going and check with a Hex editor.
9. Open your blob with the hex editor, the first line should be MSM-Radio-Update, followed by some 0s, then it should say EBT at the beginning. This marks which partitions are contained in the blob and will be flashed. Make sure none of the other (.SOS.LNX..etc) are in the blob, as then it would overwrite you. (shouldn't be there if you unpacked properly, and the filesize should be around 1.4KB)
9a. Search for whirleye's watermark, this shows the patcher worked, says "splash patcher by whirleyes"
9b. 9b is a terrorist and was deported by the TSA, move on to 9c. (bad hex joke)
9c. Open the backed up Asus blob.ebt you unblobbed, and compare the two files a tad, they should be nearly identical in length and code, except for the patched image section. If everything checks out you should be ready to flash your shiny new boot splash!
10. Now take your blob.ebt and De-knight it, stripping it of it's file extension. It is now just a 'blob' again.
11. Connect your tf and put it somewhere on your internal or external SD using adb or mass storage or whichever (I used /Removable/MicroSD/blob9000/blob)
to flash using the staging partition- you need either terminal or adb access.
the commands are:
dd if=/your/blob/here of=/dev/block/mmcblk0p4 # the last chars are zero pee four
Use adb or file manager or magic to save your blob somewhere on your transformer.
As it reboots, you should see a blue progress bar to indicate that it is flashing. It will reboot again and hopefully you will see your new splash screen.
The Blob.ebt (zipped) finished product I made. For the US .24 update ONLY RAHHHHHH!!!!(Portal gun, aperture logo, mizore-kun. LD)
The blob.ebt.asus (zipped) original unblobbed .ebt part From the US .24 update (For all dem 'muricans)
Chuck Morris.png (A picture of a trollface, yes.) [Zipped]
Any questions? Let me know if this works out for you, worked wonderfully for me!
Link to my Q&A thread, may help with a little understanding, also has pic of my patched screen: link
If I helped, hit yo' self some thanks button. :3