If you wish to upgrade your firmware from OpenWrt without resetting to stock first then you might get:
The uploaded image file does not contain a supported format. Make sure that you choose the generic image format for your platform.
.bin files are for flashing from a stock firmware.
.trx files are for flashing from OpenWrt. To convert from
.trx, strip the 32-byte header from the
dd if=openwrt-10.03.1-brcm47xx-wrt150n-squashfs.bin bs=32 skip=1 of=openwrt-10.03.1-brcm47xx-wrt150n-squashfs.trx
IMPORTANT: Verify that the output file is only 32 bytes smaller than the input file and that the
.trx file begins with
hd /tmp/openwrt-10.03.1-brcm47xx-wrt150n-squashfs.trx | head
NOTE: However, the
.trx file that is offered for download is identical to the file that you produce with
dd, so use the official
.trx instead of this method if possible!
The list of related devices: bcm47xx