Firstly, I must acknowledge the authors of the original jflash program, and hardware - thanks for your hard work.

My jlash has been hacked in the following ways;
1. Can be used for SA1100 or ARM7
2. Operates with Atmel PEROM (in this case AT49BV4096A) devices attached to nCS0.
It should be really trivial to change it for other Atmel devices.
3. Has a menu structure to erase, verify, program (with no readback test), program (with readback test) or to check before writing (only write if the current address holds incorrect data).
4. Has some write setup delays so if your hardware is dodgy (mine was when it initially lacked sufficient decoupling caps), it should still work OK.

It is quite stable, but comes with no guarantees!
Here is myjflash as a zipfile (unzips into 3 files);

unzip it into a separate directoy
unzip   nyjflash.zip

compile it with
gcc   -O2   -s   -o  DownloadFlash  DownloadFlash.cpp

then execute it (as root) with
./DownloadFlash   blobex

Where blobex is assumed to be the blob executable in binary format (i.e. the same as the standard jflash program expects, and not ELF).
 

Good Luck!!