+1 here... I was having terrible problems after my new N900 got an OTA update, which led to WiFi being unavailable. My attempts to remedy that, led to a bricked N900 (in the sense that I neither had GSM or 3G nor WiFi, making the phone nearly unusable).

Today's attempt gave me back my 3G connectivity and ability to place calls.

I flashed

RX-51_2009SE_20.2010.36-2.002_PR_COMBINED_002_ARM.bin

instead of the previously used version

RX-51_2009SE_3.2010.02-8.002_PR_COMBINED_002_ARM.bin

The reason for initially using the wrong version is that I simply was confused by the list order in the download page (the idea, that the "latest" release would be placed somewhere in the middle of the page did not occur to me, I thought it was simply a naming error, and that the "Third Maemo 5 USA variant for Nokia N900" was the most recent, even when the other list element read "latest"). Ok, logic isn't the same everywhere, and consequently I was confused.

I did the eMMC flashing each time before doing the combined, maybe this added to the poor phone's confusion? I did not boot in between, though.

Nevertheless, I am still without WiFi, will maybe give it a try tomorrow with another reflash of the eMMC. At least there is hope, after getting my 3G back, even the Wifi might return?

If somebody would be able to help with getting WiFi back, please don't hesitate.

Setup (for the moment being: Wireless distributed network, no security, which makes my hair stand on end, but I thought it might have been the routers WPA2, access control explicitly allows N900 to enter to all AP).