RU.SET?

When you quit RU it will save your current setting to a file called RU.SET.  So every time you execute RU it will stay as where you were last time, you don't need to select the register that you were reading.

However sometimes RU did not check the RU.SET carefully and this will often cause data corruption.

If RU hangs at the beginning, it's  probably caused by wrong data of RU.SET.  You can delete the RU.SET and try to execute RU again.

RU.EFI did not have this file saved, so it did not remember where you were.  The next version of RU.EFI will add this support as RU.EXE does.

Updated: RU.EFI now saved RU.SET as well started from 5.06.0125