Which HE version are you using. The Nokia site lists 4:

SU-18_2007HACKER_4.2007.45-1_PR_F5_MR0_ARM.bin 94897997 2nd FIASCO image of the OS 2007 Hacker Edition for Nokia 770 Internet Tablets
SU-18_2007HACKER_4.2007.36-2_PR_F5_MR0_ARM.bin 80019661 1st FIASCO image of the OS 2007 Hacker Edition for Nokia 770 Internet Tablets
SU-18_2007HACKER_4.2008.7-1_PR_F5_MR0_ARM.bin 89791821 LATEST FIASCO image of the OS 2007 Hacker Edition for Nokia 770 Internet Tablets
SU-18_2007HACKER_4.2007.46-3_PR_F5_MR0_ARM.bin 89791821 3rd FIASCO image of the OS 2007 Hacker Edition for Nokia 770 Internet Tablets