Right after getting my car up and running so that I could begin the tuning process and shake down other misc gremlins, my head unit went into an infinite boot loop until it ultimately shut off. I have a 2-DIN Pioneer AVH-4400NEX unit that is really awesome when it works. It has wireless android auto and great sound, lots of expansion capabilities, connectivity, etc. It's also kinda pricey to replace. So I researched if there was a way to bring it back from the dead.
It turns out that this is a common problem with those units. Pioneer apparently uses low grade SD cards for their firmware in the units and they tend to get corrupted easily. However, gaining access to the hidden SD card that holds the firmware is not simple. You need to disassemble a good bit of the HU just to access it.
Here's a pic of my unit once I got to the SD card.
If you zoom in, you'll see 2 SD card slots. The upper slot will hold media and stuff for your radio. The lower slot holds the Firmware SD card. I followed the advice and video from this post on AVIC 411 forum:
http://avic411.com/index.php?/topic/90534-how-to-fix-for-avh-w4400nex-boot-loop/
Everything there was super helpful.
Of course, in order for me to get to this phase of the process, I had to remove the radio. that meant removing the AC control knobs and panel as well as the newly installed rexypow center console. Removing the center console requires removing the seats. So I almost let this stay broken for even longer. However, I'm working on another project for the center console to solve a deficiency with the design around holding the shift boot in place from underneath.
... Anyway, I did all of that, took the radio apart, swapped the SD card with a new high quality one, and reassembled the unit.
Once that was done, I hurried back to the car to test it out and see if it either worked or if I completely bricked the unit.
Luckily, SUCCESS!!
Yeah, you can see all of the stuff removed still and I didn't even bother putting the screws back in until I knew that it worked. I didn't bother checking to see what settings and features I needed to re-setup how I had them. But I'll get to that later on (Maybe this coming weekend).
After all of this, my advice to anyone buying one of these units:
Replace that SD card BEFORE you install it. You can probably clone the SD card image that is in there if you don't want to bother with downloading the one listed in the post that I linked above. That way, you won't deal with the annoyance of finding out your radio is stuck in an endless boot-loop and you are going to have to go through a ton of work just to swap out a simple SD card.
Get your Short Antennas, Decals, and all sorts of goodies at:
https://takubanmotorsports.com
Cool, I like fixes like this. I think it was bad implementation for a separate SD card to hold the firmware but on the other hand it can be repaired opposed to having the firmware on the processor which would brick it.
Just a little tip for next time. If you get a low profile ratcheting tool that takes Philips bits that can be bought cheaply on Amazon you can remove the center console without removing the seats. It is a big time saver.
My new Sony ES headunit is very advanced but the architecture of the boards are simple and the UI is the best I have seen form any of these units.
I have some low profile ratcheting holders like you mentioned. But I wasn't able to get enough clearance for those 2 screws. Also, taking that rexypow center console out and installing is a lot more tricky than just the stock piece. So having the seats out helps with that too. hahaha.
I thought about cutting the plastic plate that blocks the lower SD card slot so that I could access it while installed in the future, but decided against it. I did put in a high end Samsung SD card that should hold up over time.
Get your Short Antennas, Decals, and all sorts of goodies at:
https://takubanmotorsports.com
I have some low profile ratcheting holders like you mentioned. But I wasn't able to get enough clearance for those 2 screws. Also, taking that rexypow center console out and installing is a lot more tricky than just the stock piece. So having the seats out helps with that too. hahaha.
I thought about cutting the plastic plate that blocks the lower SD card slot so that I could access it while installed in the future, but decided against it. I did put in a high end Samsung SD card that should hold up over time.
I have a large variety of cards for my cameras and DAPs. The real cheap stuff gets corrupted.
Although Samsung cards are good I have had two get corrupted with with music files when you modify them to where they will have a hard time reading. Not a big deal as I can unload the music, reformat and reload the files and all would be well. The Sandisk cards are the very best out of all the cards I have ever used and I have many of them. They seem to go on forever and I never had a bad one no matter how old they are.
Bah! I mispoke. I bought a bunch of Samsung Micro SD Cards for use in things like Raspberry Pi's and Steam Deck, etc. This is the one I bought to replace the one in the radio:
SanDisk 32GB Extreme PRO It's $0.30 cheaper now than when I bought it.
( https://www.amazon.com/gp/product/B09X7G85JC )
As soon as you mentioned "SanDisk" I was like "Oh wait... I researched this a LOT before buying a card and That sounds like one I bought recently". And sure enough, That is the one I went with. You can actually see the "SanDisk" logo if you zoom in on the first pic (Something I should have done before posting. hahaha).
I've bought quite a few SD and MicroSD cards over this past year so keeping my info straight is sometimes challenging. haha.
Get your Short Antennas, Decals, and all sorts of goodies at:
https://takubanmotorsports.com
SanDisk make the best cards and thumb drives but I think Samsung makes the best consumer NAND memory chips for external drives. I have a few of those extreme cards for cameras and they are dependable but there is one exception and that is my Delkin devices black series SD card which claim to be failure tested at a much higher level. I bought it because I was bored otherwise I have faith in SanDisk.
Most cards will do the job until they don't. Where they show their quality is if you delete selected images in camera or even on the computer and then keep taking images. That is when cards get corrupted. In general you should not delete images until you format the card. Most people don't know this but in general the SanDisk does better than all of them.