I have tried the procedure you listed above. Here is what I was getting as a result:
P2 Loader 0.9 (4MB-2xLV160 Flash-120nS SDRAM-10)
CPU Revision 0x0502
AT
OK
AT-X2
0x0200C000H Erase
OK
AT-X3
0x02010000H Erase
OK
The problem is that after the AT-X3 command is accepted and after I power cycle the system it is still "locked up". The other interesting thing to note is that I don't have to hit escape after the initial "P2 Loader 0.9 (4MB-2xLV160 Flash-120nS SDRAM-10)
CPU Revision 0x0502" message. It just hangs, but will accept commands. Even though I say it just hangs, I have tried to hit escape when I should, but still, of course, no luck. Any ideas?