[XPERIA X1 Q&A, Help & Troubleshooting] exrazorfish:
I bought Simore's Dual SIM Card Black 1 adapter (see this link) and it arrived by mail the other day. Fast delivery was included in the price. The version I purchased was 6.0.

The type ("1") that works with the X1 is the one where you need to chop up your SIM cards. The Dual SIM Card Black 1 adapter is explicitly listed as compatible with the X1 on the producer's site, and the X1 is even included in one of the demonstration videos on the Simore site.

The installation is fairly straight forward and the phone now behaves exactly as it did before - with the first SIM card (the SIM card fitted in slot 1 of the adapter) - except for the annoying little fact that there no longer is support for HSDPA (7.2MBit/s data traffic over the phone network) which is relatively common where I live. I only get "G" and sometimes "3G" with the Simore adapter. To get it to work this far includes turning off (inactivate) HSDPA in the Advanced Network settings menu. Otherwise it will not work.

Switching to the other SIM card takes anywhere from 15 seconds to "forever" (several minutes, if at all working). Sometimes I cannot get this to work at all and need to soft reset the phone. The connection between the second SIM card (i.e. the SIM card that is fitted in slot 2 of the adapter) and the phone network will more often than not drop after one or two minutes and this then means "no service" when you try to make a phone call. Not to mention the fact that you (often without knowing it) are unreachable. You get no notification of this. This is ofcourse extremely annoying and I would argue that unless this is corrected this is a flaw so serious that it would legally void the purchase in any civilized country.

To sum it up (the pluses and the minuses):

+ Allows you to have two SIM cards in one phone

+ Fast delivery

+ Proper installation instructions, including video featuring the X1

+ Responsive support (replies same day)

+ Nice built in menu accessible from the OS (replaces existing STK)

- Expensive

- No HSDPA support (see comment below)

- Manual incomplete for non-installation areas (how to use other feautures in the built in menu, for instance)

- Switching SIM cards takes anywhere between 15s and several minutes

- Need to turn off 3G connection before switching (otherwise will not find network)

- Often drops service (i.e. suddenly and without notice you are no longer connected to the phone network)

- Need to re-enter SMS service number everytime switch is made

- Need dual configurations on Internet settings (one for each SIM card)

When pushing Simore's support a little on the HSDPA issue I either get the standard reply ("due to some mobile limitations we are sometimes forced to use the GSM mode") or no reply at all. If I remove the adapter and reinsert only the original SIM card, I have HSDPA ("H") available again. So it is obviously their product that cannot handle HSDPA. Exactly what these "mobile limitations" are is still unclear. Atleast for me.

I find it doubtful if this is a realistic and workable alternative to carrying two cell phones. The tradeoff with HSDPA is serious enough, but the constant dropping of service on SIM card 2 is simply unacceptable. It's the same thing as having only one SIM card (but with HSDPA...).

Sorry for the long text.