I'm looking for original Speedy 1050 ROM file (8 kB in size). I would be very grateful for sharing it.

Hello,

You could have a look over here: http://www.realdos.net/MegaDownload.html
In two places it's there: Mega Speedy ATR from Guus and also in the full-rom.zip.
The names are reference to the content.
Hope this helps.

BR/
Guus Assmann