Messed mobile phone with 'dd'

[Seeker]

This mobile phone (http://forums.freebsd.org/showthread.php?t=9379) has 2 memories:
Internal - da0 - 28 MB
External - da1 - 468 MB

I decided to experiment with Internal da0, so before editing it, I did:
# dd if=/dev/da0 of=/usr/downloads/sony_ericsson.img bs=1m

After doing what I wanted. I decided to revert it to original state:
# dd of=/dev/da0 if=/usr/downloads/sony_ericsson.img bs=1m
But it failed, at 6th MB and I had to unplug it, as any operation on it would result in input/output error.

After unplugging it, mobile phone worked.

Then I decided to take a second restoring approach:
# dd of=/dev/da0 if=/usr/downloads/sony_ericsson.img conv=sync
dd: /dev/da0: Device not configured
33238+0 records in
33237+0 records out
17017344 bytes transferred in 7574.571292 secs (2247 bytes/sec)

Now after unplugging it, It can't start!
When I push ON button or plug it in PC by USB, it start blinking, white/black screen infinitively.
The only way to stop it, is to take battery out, from it.
Now, when I connect it, to PC, it can't access it, in order to attempt 'dd' image writing again.
What am I supposed to do now?!

And why did things went so terribly wrong?! :q

[fronclynne]

Search the internet for your model of phone and see if there's a way to "hard reset" it?
Take the battery out and press the power button a bunch of times, maybe (this sometimes helps to discharge the capacitors inside)?
Take it back to the phone people?

I don't know much about phone hardware, but I'd guess the answer is "Don't do that". They don't call it "disk destroyer" for nothing.

[lyuts]

I had the same behaviour on my Sony Ericsson. The difference, I didn't experiment with it. It just started blinking, just like yours. Get setool2, mbn, fbn and customization archive to fix that. Make sure you get that files for the right CID.

[Seeker]

I had to flash it.
I've used XS++ for W810i
And I already had .mbn, .fbn files(still latest), as I re-flashed it 2 years ago, when I've bought it.
Done!