The EZFlash team sent GBAtemp an EZFlash Omega to play with and it turned up this morning.
For those unaware the Omega is EZFlash's new GBA flash cart, one aiming to be the be all and end all of GBA flash carts. Initial impressions are that it could well be so, and even if not it will see you presumably able to play 99% of the GBA library with some fancy features in a fairly solid little cart. One that retailers are listing for around 40 Euros, 50 USD or 35 GBP.
The full review will cover all the troublesome games and properly put it through its paces but for now.

Out of the box
Mother 3 fan translation. Boots just fine in RAM.
Pokemon Emerald (game with real time clock). Clean ROM boots fine, saves clock as offset clock from onboard time and savestates/real time save works in it.
Various other games were tested, including a handful of prepatched games. Fine too.
Menu. Very very nippy, minimal boot times and all on a nasty little 8 gigabyte cart of the class 2 persuasion. Odd menu ordering system (possibly date related) but you can go up and down very quickly, and left and right skip pages. Otherwise simple enough.
SD slot. Moved to a friction slot rather than spring loaded used by the microSDHC version. Easy enough to insert and remove, even with my not so dainty finger. It is not impossible that you could miss the slot but it should not fall into the case if you do.
Build quality. The plastic moulding is a bit rough around the injection marks and insides but the outside finish is fine. A micrometer was fetched for the curious. Measurements taken about the thickest edge just before it dips for the sticker inlay (it is the furthest point from any support and where most would pinch it to flex).

Device	Measurement (mm)
Omega GBA size	1.337
Omega DS lite	1.213
Original EZ4	1.013
EZ4 microSDHC	0.926
EZ4 lite deluxe	1.168
EZ2	0.882
Motogp	1.254

All that said thickness is but part of the story when it comes to plastics and sheet goods. In function the Omega most resembles an original GBA cart case in that it slides together and is retained by clips once there. Do note this if you are swapping between the stock GBA size case and the DS lite size case.
Said sliding clips and mid line screw make for a far sturdier case than the sometimes maligned EZ4 microSDHC offering (no EZFlash reform to compare here). Fit and finish is otherwise pretty good, not necessarily jewellery grade but more than suitable and accurate where it counts.
The Omega lacks the "shoulders" of an original cart, as do all the others in its immediate line (the EZ2 has them) but otherwise fits fine in a GBA SP, original DS and was a bit stiff to get into an original GBA (possibly caused by differences in the alignment grooves/insets on the outside) but still worked.

PCB wise possibly a bit light with the solder paste in some places but no cold joints or anything likely to fall off, BGA looked fine as well under a loupe.
Chip numbers

Spoiler

Left to right in PCB shot below.
Spansion
71gl064a08bfw0b
0651bvb
china
http://www.datasheet.hk/view_download.php?id=1270277&file=0149\s71gl064aa0-0z_1304149.pdf
Possibly a menu/

xilinx
spartan
xc3s200a
ftg256agq1517
a5059562a
A FPGA from the main maker of such things. The 200K gate model should you be concerned about such matters.
https://www.xilinx.com/support/documentation/data_sheets/ds529.pdf

spansion
98ws512pe0fw003
748ppj40 g
malaysia
Possibly deprecated. A combined NOR and PSRAM chip.

Battery side
Windbond
25q16cvnig
1531
https://www.winbond.com/resource-files/da00-w25q16cvf1.pdf
Small flash memory chip. Possibly the programming/data chip for the FPGA

Silver top chip designated y1 in mask.
p24 54m 1603
Unknown

Under battery
8563s
Real time clock chip most likely
https://www.nxp.com/docs/en/data-sheet/PCF8563.pdf

8514n
unknown 2 pin device

3bqd
3 pin device
Unknown
v1 on solder mask

battery
Blocked by tab
3v
12.25mm
0.25mm inc cover and separator
1220 is most likely size. Maybe Duracell CR1220.

Pictures
Click to enlarge


You can see some videos, including those of the menu, from EZFlash's own teaser thread. They mirror what we saw in this initial test.

Official Usage guide
http://www.ezflash.cn/omega.html
EZFlash product homepage
http://www.ezflash.cn/product/omega/

 

[FAST6191]

The full review ?

raulpica did the GBAtemp review
https://gbatemp.net/review/ez-flash-omega.795/

It is what I would have said. Some of the issues mentioned in this thread have been lessened (power draw) or fixed (a lot of the kernel teething problems), there was the source release ( https://gbatemp.net/threads/ezflash-omega-source-code-released.510348/ , some of the builds made using it https://gbatemp.net/threads/ezflash...-kernel-1-04-and-firmware-6-0-released.514796 ) and generally things getting a bit more polished. Otherwise other than the power thing not being ideal even with the later kernels (far less than it was and playtimes will be good but not stock or like an EZ4) it is a modern design for a GBA flash cart, a device which was not so very troublesome outside of the speed requirements. Since Everdrive chucked their hat in the ring my only real reservations with these new carts has been my little GBA focused* EZ4 (or equivalents in the m3 or g6 lines) has played just about every game as it would have done on hardware, without any real traumas since about week 2 a decade or more ago and my even more venerable EZ2 only has size limitations and a need of an XP machine as the main concern. Everything else ( https://gbatemp.net/threads/official-gbatemps-everdrive-month-announcement.368176/ ) benefited massively from a shakeup and modern designs but for the GBA the answer to "so I can play just about everything without a secret handshake/finger dance and arcane tools?" has been "as long as you don't get a supercard or one of the clones" for years now. It is nice to have the fancy features inbuilt (most only really use cheats and you can do that with standalone patchers, have been able to since the days of GABSharky, though most would probably go for GBAATM at this point) and the option to more or less drag and drop (also an option on the EZ4 and the tweaks thereof these days) the entire library but yeah.

*when the DS was rising up the various manufacturers released flash carts for cheap that has limited or no GBA capabilities.

As for the in an original case I am not sure and it is sitting on my bench in the UK right now so can't check. I would be slightly surprised if it would drop straight into a sacrificial shell, or sacrificial shell with a couple of posts glued in there to hold its smaller PCB in place. I would expect it could be done with a little bit of fun with a scalpel and a rotary tool, nothing too drastic but probably not trivial either.