Okay, v40 is now out for RM-428 product code 0574994 "NA Black" (NA, not NAM?). This is the PC people used to get the early v31 release. Still nothing for 0577454.
0592207: 5800 RM-428 NAM Region US Black PR4.0 MR
0591814: 5800 RM-428 NAM Region US Sangalo Black NAVI
0574994: NA BLACK
Why "NA" instead of NAM? Might this not really be a North American PC? Where else could "NA" mean (Netherlands Antilles, North Africa)? Inquiring minds want to know...
Anyway this seems to be the leanest of the v40 firmwares:
v40 "NA" 0574994 = 131,744,800 bytes
v40 Navi 0591814 = 132,025,046 bytes
v40 NAM 0592207 = 132,618,845 bytes