All in One RAM Backup Cartridge
All in one cartridge, front side.
I couldn't find an official homepage for this "all in one" cartridge, but this is paradoxically the most valuable cartridge in this article

This cartridge model features both Action Replay support (boot ROM and 1MB/4MB expansion RAM) and 512KB backup memory storage. In simple words, it is the result of Action Replay and official memory cartridges blended together.
The backup memory is implemented with its own flash ROM chip, in the fashion as official backup memory cartridges, thus shall provide a 99% compatible (I keep the last 1% just in case of any eventual picky game that would cause problem, but this would be surprising such one exist) and in-game support for cartridge backup memory.
Using dedicated flash ROM for backup memory unfortunately means that it will be corrupted and finally no longer accessible after many write cycles, but ... this is how official cartridges worked too

However, since boot ROM and backup memory are stored in physically different flash ROM chips, the cartridge will still boot Pseudo Saturn Kai even if backup memory chip is damaged, which is one point over Action Replay where damage of backup memory ROM means the loss of nearly all other features.
Regarding firmware installed, the ebay pages selling this cartridge model I could see so far clearly mention that latest Pseudo Saturn Kai version (v6.074 at current time) is installed, and even explain the basis regarding cartridge usage such as loading a game, or accessing Save Data Manager, etc, which is quite a fair and remarkable way of doing

A review with only praises may look a bit biased (and no, I didn't received any money nor even any email from seller of this cartridge), so I would like to critic about the electronics parts used in this cartridges : theses are the same as used in Action Replay or official backup memory cartridges.
As a consequence, the technology used is no longer produced, thus probably coming from shady old stock, or counterfeit chips factory, or recycled from vintage devices. In each case, this means that in the long term, quality may not be at the meet.
An interesting related question is "Why releasing such cartridge around 20 years late ? This could exist at the time Action Replay cartridge development was still active !".
My guess about this question is that Action Replay development and/or sales team wanted to put everything (boot ROM and cartridge memory) in a single flash ROM chip, giving birth to the "if a ROM feature breaks, the whole cartridge is bricked" cartridge architecture used in Action Replay carts.
I personally like to write to flash ROM only when upgrading cartridge firmware, so that I dropped backup memory support on Pseudo Saturn Kai lite.
So my second guess is that it motivated someone to finally merge Action Replay and backup memory cartridge in a single one ? If this guess is right, then I'm glad to have indirectly contributed to the development of this cartridge

As an extra note, I could notice that several hardware variation for this cartridge model may exist, so anyone interested in purchasing such "all in one" cartridge should carefully verify it's item description page as well as features list indicated at the back side of the cartridge.
All in one cartridge : list of features available.
And finally, please enjoy a picture of each sides of the cartridge PCB

Theses pictures clearly indicate how the cartridge works, and were a great help when preparing this article.
All in one cartridge font side.
Left half : expansion RAM and glue logic for each chips.
Right half : flash ROM chips for cartridge firmware.
All in one cartridge rear side.
Flash ROM for cartridge backup memory.
Pros :
- Supports basically nearly all the Saturn games library
- Pseudo Saturn Kai is pre-installed
- There's no attempt to hide that Pseudo Saturn Kai is installed

Con :
- Cartridge backup memory may deteriorate after heavy usage.
Edit (2019/01/09) : there is also some kind of "dual boot" cartridge that seems to allow to select among two firmwares which one to boot.
Dual boot cartridge, front side
Thanks to toze3 for informing me about this cartridge 
Dual boot cartridge, rear side
Thanks to toze3 for informing me about this cartridge 
Saturn PASS
You're full of all theses cartridges to digest in a single article ? That's bad for you, because I kept the most greasy dish for the last time

Saturn PASS cartridge
This is a very simple cartridge with only boot ROM, and nothing else : no cartridge shell, and not even decoupling capacitors near the ROM chip ...
The decoupling capacitors protect neighboring components against voltage spikes : as theses apparently don't have any functional purpose, they are sometimes removed by cheap device cloners ...
Additionally, ROM chip used seems to be a
UV EPROM, easily identifiable with the small round window at the center of the chip.
UV EPROM chip detail
Yes, I did hit the snapshot key around 10 times to get
the right moment when UV window is visible 
As a consequence, firmware update requires dedicated device to illuminate the chip with UV light prior writing of the ROM and basically can't be easily done on user side.
Additionally from being technically difficult to upgrade, Saturn PASS users will also have to enjoy the custom firmware pre-installed : apparently it's a stripped version of Pseudo Saturn (or it will be an huge coincidence that log message under "Loading CD" is the same in both firmwares) with only the bare minimum remaining :
- No boot menu
- "Pseudo Saturn" name changed to "Saturn PASS"
- Addition of URL to Saturn PASS homepage
- Removal of Pseudo Saturn credits
Saturn PASS boot screen
For unknown reason they left as-is the
Pseudo Saturn is open source, so anyone with enough skills is free to change things in the firmware to their preferences. But rebranding the whole thing and trashing credits to original development team is not how open source works.
So if someone wants to thank somebody for Saturn PASS to exist, they should refer to credits displayed in Pseudo Saturn :
Copyright 2011-2015 Pseudo Saturn Team
http://github.com/cyberwarriorx/pseudosaturn
At a glance, removal of boot menu and only keeping the Pseudo Saturn exploit sounds a good idea, because that's one step less to do on user side before playing a game.
But except that point, it's complete crap : extra features (to verify if cartridge is working correctly or not, or to verify version of Saturn internals, etc) are no longer available, as well as credits page too.
Personally, I derived
Kai from
Pseudo Saturn specifically for adding features other than Pseudo Saturn exploit :
memory cartridge support in previous releases,
cheat codes in next release(s), and probably
something more in future release(s). So removing all the menus and extra features just to spare the push of one button to play a game is "no, I won't do that"

Pseudo Saturn Kai credits page is probably just a feature to boost my own ego, but I am not the only one listed there, and everybody credited contributed for free : done on their free time and without financial compensation. So muting them is definitely not an option. Also, I made several graphic improvements when displaying credits, so I hope you will enjoy them in next release

To finish on a positive note about Saturn PASS, it should be mentioned that its price is relatively reasonable : 350 Thai Bath = around 10 US Dollars, which makes this cartridge affordable for Thailand users

Pro :
- Affordable for Thailand users.
Cons :
- Can't upgrade firmware.
- No credits to original firmware developers.
PS : I heard about this cartridge from
furrtek. Special thanks to him for the information
