is it a JTAG or RGH Console?
You would have to change the resistors like the pic below:
This is a pic from the XD Card mod guide written by "mastag21"
And you would need to extract the KV from your BB Nand backup then create your new nand image using 360multibuild or Jtool depending on whicheverone you want to use.
problem is going to be if you have the CPU key or not. If you dont you will need to load Xell first to get it. if it is a JTAG then no problem just flash the Xell.bin file over and boot it up. if it is a RGH then you will need a donor Jasper 16mb image and then make the ecc file to flash over. then flash the ecc file over and run the reset glitch hack to load xell.
It can be done just will take some playing with it. Also you will need to know the LDV value from the nand backup you had on BB nand. you may even be able to create the ECC file directly from the BB nand to flash to the 16mb tsop. keep us informed. I always wanted to play with a conversion like this.