There was no need to start a new thread.
And please enclose the code samples you are posting into <pre> and </pre> tags, you will get similar look than the code below.

Are you sure the RAM is mapped to code memory space for reading?
Check, how the RAM's control pins are connected, there should be some relation between /OE and /PSEN.
Alternatively, you can try to modify the bootloader in such way that immediately after writing a byte into the RAM it reads it back using MOVC and checks against the byte to be stored.
Something like:

load4:          acall gethex        ; get data byte
                movx @dptr,a        ; store in ext. ram
                mov  r2,a             ;store the data to r2
                clr  a            
                movc a,@a+dptr         ;readback from (code mapped) RAM
                clr  c 
                subb a,r2              ;compare with stored
                jz   load4OK
                mov  dptr,#errormsg                       ;error - print a message
                lcall outstr
                ljmp  error
errormsg:       cr,'Data readback mismatch',0
load4OK:
                inc dptr

Jan Waclawek