Not sure about the first part of all that, but I tried adding a second reco to my system yesterday after going to .37 alpha and I got the same diskless setup failed, but I thought it was because the device registered as an amd64 (hadn't been a problem before) but thought that a web admin change to i386 and rebuilt would fix the problem- hadn't had the time
Not 100% sure what issue you are describing here... but just in case it helps - just changing the MD architecture field to i386 will not change the architecture, you must use the rebuild image button. It selects AMD64 because your CPU is capable of it and so builds all the boot files in that mode. Once done, if for some reason you need i386 (preferable), you need to change that field then rebuild the image. Note: any changes you made to the configuration of that MD will be lost by rebuilding the image, so you will need to make those changes again after the rebuild (such as adding/removing/reconfiguring modules, drivers, scripts, etc). So the sequence should be: boot new MD to create AMD64 image, modify the architecture field to i386, rebuild the MD image, make all configuration changes to the image.
Another note: the MD images are decompressed from a purpose built bzip'd archive file, they are NOT generated from the core's own files and configuration, so do not assume that any config changes, driver updates, etc you perform on the core will pass to the MD.