C :: Copying Between Arrays?

I'm doing a 1Mb memory dump like this:

Code:

for (int i = 0; i < 0x00100000; i++) {
dump[i] = *(chipmemory+i);
} // i

Then I save the 1Mb "dump" array to a file, and the file contains the data I expect.

The problem arises when I try to write data back to the array beginning at the "chipmemory" pointer:

Code:
unsigned char msga[18] = "SOME MODIFIED DATA";
int address = 172378;
for (int i = 0; i < 18; i++) {
*(chipmemory+address) = msga[i];
address++;
} // i

Is this the correct way to write back to an address 172378 bytes from the "chipmemory" pointer? or is my code broken somewhere else?