Nowadays you are able to hack Nokia E51 new firmware 300.34.56 with no
confusing too much. So, any unsigned applications can be easy
installed to your phone. However, there is possibility to damage your
phone each time you change it mod, so you should hack E51 by take your
own risk. Once you’re ready, here’s the ways to hack firmware
300.34.56 of Nokia E51:

Install MapDrives v1.00 DiskAdmin Unsigned.sis
Install Jbak Taskman 1.00
You need to have drive E: on your PC, there is one exist so cover it.
And then copy MapDrives.txt into it.
Create E:/Hack/sys/bin/installserver.exe and copy installserver there.
Running JBak Taskman software and follow these steps:
-Go to Menu => Tools => Program start
-Search and select MapDrives you’re created
-Press More => Programs Rule
-Select “AutoStart” and press OK

After restart your Nokia E51 phone you can delete MapDrives. It was
important to exit form JBak Taskman completely before delete
MapDrives. And then install MapDrive_JBakTM_EMU_Y for N82, N95,
N95-8GB, E71. Those all phones with Y: drive, else, better choose
MapDrive_JBakTM_EMU_Y if you have H: driver because some has
experience getting an error when installed in Y. If all had to do, now
you can start the application.

Finally install Modo you can modify the system date if you want it,
That was something like 2008-08-09 or ahead. And then copy
Installserver to C:/sys/bin/.

Here all download files but you should sign if you want to get it.