diff --git a/reference/nim/proof_input/README.md b/reference/nim/proof_input/README.md
index 9503c0f..6993228 100644
--- a/reference/nim/proof_input/README.md
+++ b/reference/nim/proof_input/README.md
@@ -13,19 +13,21 @@ use real data.
     $ ./cli [options] --output=proof_input.json --circom=proof_main.circom
     
     available options:
+     -h, --help                         : print this help
+     -v, --verbose                      : verbose output (print the actual parameters)
      -d, --depth      = <maxdepth>      : maximum depth of the slot tree (eg. 32)
      -N, --maxslots   = <maxslots>      : maximum number of slots (eg. 256)
-     -c, --cellSize   = <cellSize>      : cell size in bytes (eg. 2048)
-     -b, --blockSize  = <blockSize>     : block size in bytes (eg. 65536)
+     -c, --cellsize   = <cellSize>      : cell size in bytes (eg. 2048)
+     -b, --blocksize  = <blockSize>     : block size in bytes (eg. 65536)
      -s, --nslots     = <nslots>        : number of slots in the dataset (eg. 13)
      -n, --nsamples   = <nsamples>      : number of samples we prove (eg. 100)
      -e, --entropy    = <entropy>       : external randomness (eg. 1234567)
      -S, --seed       = <seed>          : seed to generate the fake data (eg. 12345)
-     -f, --file       = <datafile.bin>  : slot data file
+     -f, --file       = <datafile>      : slot data file, base name (eg. "slotdata" would mean "slotdata5.dat" for slot index = 5)
      -i, --index      = <slotIndex>     : index of the slot (within the dataset) we prove
      -k, --log2ncells = <log2(ncells)>  : log2 of the number of cells inside this slot (eg. 10)
      -K, --ncells     = <ncells>        : number of cells inside this slot (eg. 1024; must be a power of two)
-     -o, --output     = <inupt.json>    : the JSON file into which we write the proof input
+     -o, --output     = <input.json>    : the JSON file into which we write the proof input
      -C, --circom     = <main.circom>   : the circom main component to create with these parameters
 
 You can generate only the `.json` or only the `.circom` file, or both at the same 
@@ -33,3 +35,8 @@ time.
 
 There are some default values for all the rest of the parameters.
 
+NOTE: When using actual files for the slot data (which is untested :), you will 
+need _all_ slots to be able to compute the dataset root. The convention used is 
+that you specify the base name of the file, say `"slotdata"`; and the individual 
+slots file names are derived from this to be for example `"slotdata5.dat"` for 
+the slot with index 5 (note: indexing starts from 0).
\ No newline at end of file
diff --git a/reference/nim/proof_input/src/cli.nim b/reference/nim/proof_input/src/cli.nim
index f011314..313ea72 100644
--- a/reference/nim/proof_input/src/cli.nim
+++ b/reference/nim/proof_input/src/cli.nim
@@ -64,6 +64,8 @@ proc printHelp() =
   echo "$ ./cli [options] --output=proof_input.json --circom=proof_main.circom"
   echo ""
   echo "available options:"
+  echo " -h, --help                         : print this help"
+  echo " -v, --verbose                      : verbose output (print the actual parameters)"
   echo " -d, --depth      = <maxdepth>      : maximum depth of the slot tree (eg. 32)"
   echo " -N, --maxslots   = <maxslots>      : maximum number of slots (eg. 256)"
   echo " -c, --cellsize   = <cellSize>      : cell size in bytes (eg. 2048)"
@@ -72,7 +74,7 @@ proc printHelp() =
   echo " -n, --nsamples   = <nsamples>      : number of samples we prove (eg. 100)"
   echo " -e, --entropy    = <entropy>       : external randomness (eg. 1234567)"
   echo " -S, --seed       = <seed>          : seed to generate the fake data (eg. 12345)"
-  echo " -f, --file       = <datafile.bin>  : slot data file"
+  echo " -f, --file       = <datafile>      : slot data file, base name (eg. \"slotdata\" would mean \"slotdata5.dat\" for slot index = 5)"
   echo " -i, --index      = <slotIndex>     : index of the slot (within the dataset) we prove"
   echo " -k, --log2ncells = <log2(ncells)>  : log2 of the number of cells inside this slot (eg. 10)"
   echo " -K, --ncells     = <ncells>        : number of cells inside this slot (eg. 1024; must be a power of two)"
diff --git a/reference/nim/proof_input/src/slot.nim b/reference/nim/proof_input/src/slot.nim
index 08d13d0..3957011 100644
--- a/reference/nim/proof_input/src/slot.nim
+++ b/reference/nim/proof_input/src/slot.nim
@@ -12,15 +12,13 @@ import types
 #
 
 const exSlotCfg = 
-  SlotConfig( nCells:   256  # 1024
-            , nSamples: 5    # 20
+  SlotConfig( nCells:   256  
+            , nSamples: 5    
             , dataSrc:  DataSource(kind: FakeData, seed: 12345)
             )
 
 #-------------------------------------------------------------------------------
 
-# (10852671575406741732, 3735945064, 2557891771)
-
 {.overflowChecks: off.}
 proc genFakeCell(globcfg: GlobalConfig, cfg: SlotConfig, seed: Seed, idx: CellIdx): Cell  =
   let seed1 : uint64 = uint64(seed) + 0xdeadcafe'u64