Just thinking out load

You did format the pen and you did rename it to update and you have done alt-l fingers pressed down
Try hitting alt- L 20-30 TIMES REAL FAST. and have you tried to get into recovery with no usb stick inserted dont know if you can but worth a try

Other than that mate not sure what is wrong

I did format 2 different pens (4Gb and 8Gb, one of these I used to flash beta 1) with Win7 disk tool
16k, 4096k and standard cluster size FAT32; FAT16
also I have tried HP Format Tool for both of them
I coped beta 1 (1b3a6b1aa9fd.mp-signed-ota_update-b55579) and beta 2 (mp-signed-ota_update-b58801.15d88c27-t)
I did rename it to update.zip, also to just "update" and I have tried unpack them to the root
Also I tried use both flash pens at the same time
I did hold Alt-L, Alt-S, FN-Left. Also I just pressed buttons once and a couple times (not 20... but 10 times I'm sure)
And, yes, I did tried without flash (by the way I think it should work)

No one tells me about green led on the keyboard, should it work?
My English is not perfect, I'm from Russia, so please excuse me and please ask again if I answer something wrong

The green led only stays on for a few secs when switched on, just one thing you do not have both updates on the stick at the same time do you as that might cause problems and when you said you renamed it update.zip just making sure you did not put in zip all you neeed to type is update.
If you have tried it all then it may be that you have no recovery on there just guessing i will look around and see if i can see anything about it

It looks like to me you have lost recovery so i believe the post below will help you

revue/topic254.html

I don't think that will work as he needs to be able to enable the settings in the OS to allow ADB to connect. Without some type of terminal output to see exactly what's happening, I'm lost on this one. I'm leaning towards something with the bootloader or kernel itself at this point as it seems to hang before it's able to perform any functions or accept any input.

I'm sure you have by now, but in case you haven't, try the tips in this thread. One suggestion that worked for several people was to only press the connect button once rather then hold it.

Thanks a lot, I will look at this topic.