[Android Software/Hacking General [Developers Only]] gee one:
I don't have extensive knowledge, but I did watch a youtube video once. Nvflash is used on several devices, so check out the acer/zoom/transformer forums. I think it also has some roots in graphics cards, so some of the tweaker forums might have some useful insight about syntax.

Nvflash started
nvflash action [options]
action (one or more) =
--help (or -h)
displays this page
--cmdhelp cmd(or -ch)
displays command help
--resume (or -r)
send the following commands to an already-running bootloader
--quiet (or -q)
surpress excessive console output
--wait (or -w)
waits for a device connection (currently a USB cable)
--create
full initialization of the target device using the config file
--download N filename
download partition filename to N
--setboot N
sets the boot partition to partition N
--format_partition N
formats contents of partition N
--read N filename
reads back partition N into filename
--getpartitiontable filename
reads back the partition table into filename
--getbit filename
reads back BIT into filename
--getbct
reads back the BCT from mass storage
--odm C Data
ODM custom 32bit command 'C' with associated 32bit data
--go
continues normal execution of the downloaded bootloader
options =
--configfile filename
indicates the configuration file used with the following commands:
--create, --format_all
--bct filename
indicates the file containing the BCT
--sbk 0x00000000 00000000 00000000 00000000
indicates the secure boot key for the target device
--bl filename
downloads and runs the bootloader specified by filename
--odmdata N
sets 32bit customer data into a field in the BCT, either hex or
decimal
--diskimgopt N
sets 32bit data required for disk image convertion tool
--format_all
formats all existing partitions on the target device using the config file,
including partitions and the bct
--setbootdevtype S
sets the boot device type fuse value for the device name.
allowed device name string mentioned below:
emmc, nand_x8, nand_x16, nor, spi
--setbootdevconfig N
sets the boot device config fuse value either hex or decimal
--verifypart N
verifies data for partition id = N specified. N=-1
indicates all partitions
Intended to be used with --create command only.
--setbct
updates the chip specific settings of the BCT in mass storage to
the bct supplied,used with --create, should not be with --read,and
--format(delete)_all,format(delete)_partition,--download, and--read
--sync
issues force sync commad
--rawdeviceread S N filename
reads back N sectors starting from sector S into filename
--rawdevicewrite S N filename
writes back N sectors from filename to device starting from sector S

Here's what I use

nvflash --bct transformer.bct --setbct --configfile flash.cfg --bl bootloader.bin --odmdata [device specific odm data] --sbk [mysterious sbk] --sync

All the files are device specific and the flash.cfg is where all the partitions and sizes are specified. Nvidia used to have a developers website that had a generic HC and GB rom. I flashed it, but was configured for different screen sizes/trackpad, etc.

If you are going to format the device, then you will use the --create flag and I think you need the flash.cfg file.