Choosing the right SSD to install in the WWAN slot (X230, X240, and T480)

[br1anstorm]

For years I have been a devotee of the T-series, mainly a trusty and solid T430, which was succeeded by the T430s which I am currently using.

On each I installed a 256GB SSD in the WWAN slot, because I like to have a dual-boot arrangement, So I retain Windows and its Boot Manager on the original or main drive, and have Linux Mint or LMDE, with its GRUB, on the SSD in the WWAN slot. This keeps the two OSs separate, and enables me to boot whichever I choose. I use Linux most of the time, so I set that drive to be first in the boot order in BIOS. I only keep Windows in order to use certain Windows-only image-editing software.

I have in recent years acquired a couple of refurbished X-series (one X230 and one X240). Aside from being smaller and lighter, their IPS screens are nice! Both only have their original drives with Windows 10 installed. So I am now looking at getting the right model of SSD to fit into each of their WWAN spaces. And I'm struggling to find clear guidance on exactly which model and spec of SSD is right for each. It doesn't help that the details in many online listings and YouTube clips are less than precise.

I think I have figured out that the X230 WWAN slot takes the same model(s) of SSD as my T-series machines: that is, a Kingston SKC600MS256GB, which is an Msata drive - or the equivalent from other makers, like the Samsung PM830 Msata 256GB. No doubt there are other brands too. The size is 2242, the connection type is SATA (or is it mSATA?), the connector end has a single notch, and the other end has two holes, one in each corner, for the mounting screws. Is my research correct, and are there other specific details I need to check?

As for the X240, this apparently needs a different type or configuration of SSD to go in the WWAN slot. Apparently an "M.2 2242" SSD - and it has two 'notches' (B and M keys) in the connector and a single screw-mount at the other end. And it has to be SATA, not NVME (?). I've seen reference to Transcend MTS400 SATA III models (and various Chinese brands like KingSpec and Dogfish). Where I get confused is where some alternative listings refer also to NVME, PCI-e and Gen3x2 or 4x4. How significant are these in identifying and choosing what would fit and work in a ThinkPad X240?

And to complete the picture, I have just got a T480, with Windows 11 (yay! or ugh!) and I want to put an SSD into its WWAN slot in order to have Linux available too. The requirements seem to be different again. It needs an M.2 NVME 2242 SSD - I think also with the B and M keys, and single screw mount. But I saw somewhere that only certain SSDs will work in the T480's WWAN slot: the one specifically recommended was the Western Digital SN520. I've seen Toshiba and Transcend mentioned but with comments that they may not be recognised and/or run very hot....

So any help in clarifying and deciphering exactly which SSDs will be suitable to put into the WWAN slots of the X230, X240, and T480 would be much appreciated! I want to make sure I order the right one for each machine.

[axur-delmeria]

The X240 WWAN slot requires an M.2 2242 SATA SSD, like this one from Transcend.

The T480 WWAN slot requires an M.2 2242 NVMe SSD with B+M keying, like this one from KingSpec.

Note that the two look identical (both are M.2 2242 with B+M keying) but carry different signals (SATA and PCIe respectively).

Most M.2 2242 NVMe SSDs these days are M-keyed like the usual M.2 2280 NVMe SSDs, which don't fit in the T480 WWAN slot because of the B-key.

Another approach is to get an M.2 2230 NVMe SSD (almost always M-keyed) which is becoming more common as it's used in the Steam Deck, ROG Ally, and similar handheld consoles and use a B+M to M key adapter like this one. However, many M.2 2230 SSDs don't work with this adapter: this is because some 3.3V pins on the M-key slot are not connected (the B-key notch takes their place), and apparently many SSDs won't power up without them. The solution is to solder a wire from the other 3.3V pins to the disconnected ones, as seen in this photo of a different adapter.

There are some B+M to M-key adapters that have the 3.3V pins properly routed, but are 2280 size. You'll have to cut it to 2242 size, but the adapter itself adds some height, and the M.2 SSD may even touch the bottom cover (not a good idea TBH).

[br1anstorm]

Thanks @axur-delmeria, that helps a great deal.

I think I'll skip the idea of using an adapter, or modifying/resoldering pin-connections. Such things add complication, and as you point out, don't always work.

So I'm going to focus on finding SSDs with the right spec, such as those you have suggested.

If there aren't good sources in the UK, I might take a look at the (Chinese) aliexpress listings....

[axur-delmeria]

This one will probably work but it's only 64GB, and you'll need a 2230 to 2242 extender bracket.

Older M.2 2242 NVMe SSDs like the WD Blue SN520 and Toshiba RC100 are known to work on the T480 without modification, same with the Hynix BC501.

[br1anstorm]

Progress.....! I have sourced a Western Digital SN520 256GB M.2 NVMe SSD and successfully installed it into the WWAN slot in the T480.

I already have a Kingston SKC600 mSATA 256GB which should go into the X230.

And I found a Transcend M.2 2242 SATA 256GB SSD for sale online which ought to arrive in a week or two; that can go into the X240.

That will get me up to date.

Thanks for the help and advice....