Can I boot into 32 bit mode in Lion without pressing the keys?

Try rebooting manually hold the 3 2 keys, verify or deny you kernel:

Apple() --> About this Mac --> More info --> Overview -->SystemReport

System Software Overview:

64-bit Kernel and Extensions:

No if it is boot into 32-bit,

Yes if it is booted 64-bit

http://support.apple.com/kb/HT3770

http://support.apple.com/kb/ht3773

If you can manually boot into 32 bit kernel, then yes.

Will not effect your personal files.

Hello there,

I looked at the man pages for systemsetup and the option was still there.

So I decided to run it with the appropriate options (same as defined in ht3773).

I confirm it works!

Enjoy...

Good computing ShomikB !

Fantastico! Your instructions to reboot LION in 32bit worked like a charm and I can now see and sync with my Sony eReader ! Thank you 😎

Now we just need to get this work-around to Sony customer support ...

I want to thank you for answering a question I had about how to get my Sony ereader to be recognized after I had upgraded to Lion. I have been so frustrated that I can no longer use my Sony ereader to download and read library books. This is why I bought it. I contacted Sony support and the assistance they gave me helped me to download the library books to the ereader, but the books would not open. It has been very frustrating. I found your step by step assistance on this and am very grateful for it. Your instructions were clear and easy to follow and answered my concerns. It really felt good to being able to determine that my computer by default operates in 64 bit mode and then how to boot the computer to 32 bit mode. It worked and the books downloaded, the ereader is recognized again, and I can open the book and read it. Thank you again!

I'm using a MacBook Air that's only two months' old with Lion pre-installed. With 3-2 key held down, it stills starts in 64bit mode. Does this model not have support for 32bit mode any more?

I've got the same MBA as you do and this manual boot procedure works just fine for me. I've used it just once to update my Sony NEX's firmware and it worked perfectly.