Hello guys. I just bought a 2nd-hand HTC HD2. Just flashed to Android.

There's a question that bothers me.
I've noticed that the cable and USB port is exactly the same with my Nokia 5800XM. Can I use my existing 5800XM's cable to charge battery and do transfer files via USB? Will it hurt my phone & battery?

Yes. they are all microUSB to USB cables.
I flashed this build onto my sis's device, so far, so good.

btw, this rom gives you only little free internal storage left, so you might run into problems installing apps (lots of) later on, even if you move all apps to SD, certain apps are not movable and need to remain on internal storage.
the workaround is : partition your SD card, one standard FAT32 partition and the other 1GB ext4 or ext3 partition. this way, the phone will see the ext4 partion as 'internal storage and you will not run out of internal storage when installing apps.