Checksum error after crash install Android I wanted to upgrade my Android phone (Acer Liquid Ferrari) from 2.2 to 2.3 but it crashed => I can't turn on my phone,

When I do a clean boot (power + vol up + vol down) there are no problem but my phone doesn't reboot

When I want to go into Recovery (power + vol up + cam) there are an error on the checksum

Partition: checksum
 splash: chsum =00000000 OK
 boot:chcksum=8fa17e51 != 0021fde4 **fail**
 recovery:chsum =00000000 OK
 system:chsum =00000000 OK
=====
&lt;&lt;FAIL&gt;&gt;


So when I want to do adb devices I have error device not found. The driver is correctly installed on my computer

How can I launch the recovery mode ?

Thanks
I solved my problem by connecting my phone to usb and pressing Vol Up + Cam + Power for await my PC recognize the device. 
After that, I use Acer Tools to flash my device with the bin of Android