Since 2012 September, shipping Digi Connect ME 4MB modules (DC-ME4-01T-C) might have an updated flash chip, Micron M29DW323DB, which is not supported by the old linux kernel 2.4.22 flash driver. Programming a linux image into a Digi Connect ME 4MB module with this flash chip will cause the unit to no longer boot properly.
Modules from the same batch may have Micron, Numonyx or ST flash chips with similar chip fingerprint: M29DW323DB, but the Mircron will not be detected by Linux.
Currently there is no updated flash patch available from Digi. Please check here for patches
To recover your module, try shorting module pins 18 (MFGI) and 20 (INIT) to ground (e.g. pin 16), if all goes well you'll initiate the recovery process as described here.
You might try to downgrade to a module with 2MB flash chip DC-ME-01T-C which has flash chip either ST M29W160EB70ZA6E since 2008 or Spansion S29AL016D70BFI020 or Spansion S29AL016J70BFI020 since 2010.
However since LxNETES-2.3 uClinux 2.4.22 is not supported anymore, Digi can't guarantee anything for 2MB flash chip is supported by LxNETES-2.3 or future flash chip changes will be supported. You are on your own to check if 2MB variant might work for you, while modules from same batch may have ST or Spansion chip.
Jun 28, 2019