After a lot of searching and help from this site I finally managed to bypass frp on my Archos Sense 55DC. So I thought some of the problems I had might be the same as others encounter.
I used the MTK Smart Phone Flash Tool and found a matching Scatter File for the MTK6737M for the phone.
I selected the Format tab and chose Manual Format Flash with begin address 0x6A00000 and length 0x100000
Tried "start" and then connected phone. Phone needs to be off when connecting and I did read that it helps to hold in volume buttons when connecting. Not sure if it helps but I did it anyway.
I kept getting GET_DRAM_SETTINGS_FAIL (5054) even though I had correct scatter file. Eventually found that even though I was not downloading firmware and just formatting I needed to have selected valid files selected for the download partitions. So, found an Archos 55DC firmware download then when I selected the scatter file within that unzipped download it also listed the file location of the download partitions (see screen shot). I made sure all the download sections were unchecked then went back to "Manual Format Flash" pressed start and reconnected the the phone. After a few seconds go the OK dialog and the phone was unlocked.