Managed to modify a 39gs into a 48gII

[Zweb]

Here are the results:
   
File manager, 256KB RAM:
   
Equation library:
   

Here are the instructions about how to modify (I'm not native speaker, sorry for my poor English):
1\ get a 39gs and a 48gii
2\ disassemble them
3\ connect your 48gii to computer via JTAG.
(the JTAG pin lies in J2 connector, which pinout is TCK TDI TDO TMS GND GND
4\ dump the ROM to your PC (2MB). (I used the SEGGER J-Flash software since I'm using SEGGER J-Link ARM-OB)
5\ desolder the original 39gs ROM chip (SST39VF800, 1MB)
   
6\ solder a new 2MB ROM chip (I used SST39VF160)
   
7\ connect your 39gs to computer via JTAG and flash the ROM which you have dumped in step 4.
8\ Enjoy~ May be a keyboard sticker is needed.

[andylithia]

Awesome!
Since HP-39gs was beaten by Ti calculators especially in the Chinese education market, millions of package-less unused unit came out as e-garbage, you can purchase as many as you want for only about 8~15$ per unit (including shipping in China) on taobao, this modification might be extremely useful!

[PANAMATIK]

(04-25-2015 02:04 PM)Zweb Wrote:  Managed to modify a 39gs into a 48gII

8\ Enjoy~ May be a keyboard sticker is needed.

Great! Congratulations!

If there is any print office for custom keyboard reprinting, it would get many orders from here. Also if it could produce new HP Prime buttons.

Bernhard

[Tugdual]

(04-25-2015 03:58 PM)PANAMATIK Wrote:  If there is any print office for custom keyboard reprinting, it would get many orders from here. Also if it could produce new HP Prime buttons.

Bernhard

Hey if you have any solution for that I send my 34s in the following minute!

[osfg]

(04-25-2015 03:58 PM)PANAMATIK Wrote:  

(04-25-2015 02:04 PM)Zweb Wrote:  Managed to modify a 39gs into a 48gII

8\ Enjoy~ May be a keyboard sticker is needed.

Great! Congratulations!

If there is any print office for custom keyboard reprinting, it would get many orders from here. Also if it could produce new HP Prime buttons.

Bernhard

There is little space on the keyboard of 39gs so use sticker is unsuitable.I'm worried about the
Durability of the mark that mark pen made.So I had never updated any 39gs.(My poor English.......)