q2496e upgrade problem

We have a pair of M1306 modems which tried to upgrade to 657e_full_q2406b.dwl using HyperTerminal
and AT commands to upload the new firmware. Many other modems were upgraded using the same
procedure with success.

After uploading this firmware the modules didn’t work. No led flash and response to AT commands.

The modems still responds to DWLWin, so tried to upload the files pro-dwl.wpb and q2406b.e2p
but the module do not recover and keeps not flashing led nor answering AT commands

Opening the modem we checked both modems are using Q2406E and not Q2406B. Our distributor says that difference
is only memory size and the file sould work, but there is a great coincidence that both modems using
Q2406E do not work when upgrading to this firmware. The motherboards of the M1306 were tested with
other working Q2406B module and both are OK. So it must be the firmware.

Can anyone help me to find suitable firmware for Q2406E, please ??