I'm attempting to add whitelist support on this laptop, and I'm aware of the middleton's bios. I'd like to make a full backup of the BIOS before hand and I've tried a couple methods without success. Also being non-EFI and very old excludes modern documention and the embedded security processor present. I hooked up a SOIC clip with SPI and detected the chip with Flashrom but the binary file it grabs is all 0's. I also tried to make a backup in windows using WinPhlash64 but it requires a flash image to even backup so I pulled a .FL1 file from Lenovo's last OEM BIOS update but complains of error -103 size missmatch. Lastly I went into RW everything and was able to see some data constantly in activity in the binary viewer so that's probably the embedded security chip. Using RW everything I was able to pull the ACPI table into a binary file. Is there some easy method I'm not aware of to do a full BIOS backup?
Using "flashrom -p internal -r backup.rom" in Linux (where internal programmer read/write is supported)? Not sure whether it supports your laptop though, but no harm to try reading...
You might have to flash the Middleton's BIOS then in order to back up the BIOS, that is, I believe you can set the WinPhlash64 to back up existing BIOS before flashing the new one. I don't think you can just back up the BIOS only. One other thought: For SOIC clip, did you check your clip was not loose and markings matched up? Sometimes it's hard to ensure a good connection. Otherwise chip might need to be de-soldered to be read since clip might be trying to power up the board it is attached to as well.
There's actually a option to enable backup only but I read somewhere the tool has a limitation that it requires a source file even when backing up because it gauges what the BIOS size is from the source. So if you offer a 2MB source image and your bios is 4MB it won't copy it all. The problem is when I tried it with the OEM lenovo update it said size mismatch but I didn't think to try it with the Middletons image! I thought that at first and used a bunch of individual "clip probes" so remove any question and still nothing so you're prob right it's being influenced by surrounding circuits. I don't have a heatgun so I don't feel confident enough to desolder it.