TL;DR: Having trouble writing with the Arduino Uno and RFID255 Board? Switch RST/9 to RST/5. Double check it is all working before writing via the Addicore RFID library and example using Arduino IDE. If you are getting time out errors or such on 0.3, try 0.2. Don't touch the tag to the writer before Amiibomb has said to remove it and place it back on (for me this happens right after hitting 'Create Amiibo' or whatever it says) as this can burn a tag and make it useless.
Okay forgive me if this was posted somewhere else in here or elsewhere - I couldn't find it.
I finally got all my stuff in from AliExpress (Paid 1.61 for the Uno, Wires and NFC Board). After purchasing a Soldering Iron and Solder (Own 3, couldn't find 1) I sat down to get to it!
Well Amiibomb just sat there going 'Waiting for NTAG' and saying 'Not Connected'.
Okay so I try doing it via Arduino IDE - Error in Communication.
Check all my solder work twice, swapped out different jumper wires, still nothing.
Given up at this point honestly, did a bunch of random troubleshoot type things and just didn't get anywhere. Went scrolling through this whole thread and countless others to no avail. I finally laid down for bed, opened up the AliExpress app and looked at the reviews for each piece. Only a few bad reviews and I figured I was one of the unlucky few to get a bad board.
Someone said they had trouble with the RFID board something about I2C (don't ask me). I set out thinking it may be a program to tell me which pins are working or such (in a sense the Arduino sketch was just that). It didn't work and I don't know exactly how but I ended finding someone else having the same problem with the I2C sketch. A person responded saying to download a certain library, switch PIN 9/RST to PIN 5 and a few other things relating to the I2C sketch. Well I switched the pin, loaded the sketch, swiped a tag and ... it read!
I go into Amiibomb, flash the Uno and select a random dump file. IT WROTE! Tested it on my BOTW Zelda/Switch - it worked!
Then I learned a few more quirks with Amiibomb - I was using 0.2 and 0.3 randomly trying to figure if it was a problem with one or the other. In the end I ended up doing everything with 0.2 (I believe 0.3 kept giving me 'Timed out' messages, which ruins the tag). On to Quirk 1 - When hitting 'Create Tag', DO NOT hold the tag to the writer. Mine never showed that it was connected or anything until I hit 'Create Tag' at which point an error dialogue would pop up and tell me to take the tag off the writer and put it on again. ONLY AFTER THIS should you place the tag on the writer. If you do it before, it won't read the tag, it won't detect the tag, nothing. I lost about 3 tags doing it this way. Second quirk cost me a few more tags in 'Time out' messages, which didn't seem to occur in 0.2. Third Quirk and this may be common sense or stupidity but you don't need to 'Rub' the tag on the RFID board - this could ruin the tag, not entirely sure. I just noticed the tags didn't really work before then.
I would recommend anyone download the Arduino IDE and the Addicore RFID Library, add it and then load the example MFRC255. Upload it to the board, then go into the Serial Monitor, select Both on one of the drop downs - think its LNC and RC? I don't have everything hooked up at the moment. The baud rate should be filled in and then just tap a tag on or near the RFID board and see if it reads. Do this first to make sure everything is working before trying to write to them - as I said, for one reason or another you can burn a tag by just trying to write to it and having an error appear - or not even appear!