No you cannot use a umd be to downgrade psp software
Firmware updates are specific to certain models of Macs. It's possible that the firmware you're trying to install is not the correct firmware for your particular Mac. If the firmware was downloaded by going to  -> Software Updates (or just by running Software Update), then the firmware is likely the correct version, and may just be corrupt. If the firmware was downloaded from Apple's Support Downloads, then it is most likely the incorrect firmware for your Mac.
jailbreak your ipod using blackra1n.com (the easiest fastest and safest way to jailbreak) then down load the Cydia app off of the blackra1n app and apply the theme using Winter board, which will automatically install after using Cydia. Note: blackra1n works with ipod touch firmware 3.1.2, if you already upgraded your firmware to 3.1.3, downgrade your ipod's firmware to 3.1.2 Also, if you already have 3.1.3, you can jailbreak with a new software called Spirit, which is just as fast and reliable.
The Xbox 360 lt 3.0 is the new firmware (O/S) for the console. You will be given a chance to download the firmware when you turn and log onto your Xbox live account. However, you can just download the firmware yourself, put it on a CD and install it like that.
If you are using Offical Firmware you just go to the settings tab If using Custom firmware Completely turn off the PSP By holding the Power switch for about 10 sec then hold R while starting
You must have a firmware installed other than the Official Sony firmware in order to use psp-pda. If you need help putting a "Custom Firmware" onto your psp you can find an almost limitless selection of tutorials online. Then you just need to place it in the game folder.
== First you need to install firmware onto your MicroSD Card. If you have the official R4DS, this comes in a CD. If not, you will need to go to the manufacturer's website to download their custom firmware. Usually you just copy a "_DS_MENU.dat" file and a folder to the root of your MicroSD Card.
I'm not sure what you mean by "the mod" but I think you may be referring to a "custom firmware". If so, you can safely format your PSP's memory stick without removing the custom firmware. This is because the custom firmware is stored in the internal PSP flash memory, not on your memory stick. If you want to remove the custom firmware, you will need to just install an official firmware onto the psp. The easiest way to do this is to put in a PSP game that comes with a firmware upgrade and choose that option. Then I would recommend having the psp do a Network Update.
If you are using a regular version just upgrade your router with the latest firmware. (google keywords: wpn824 firmware > preferably use the link that's from netgear's own website...) however if you use the UPC or other cable internet provider's version, you need a modded firmware... read up on it on google... (keywords: hex edit WPN824 firmware)
I just spoke with technical support, there are no firmware updates for this model (I have one as well).
You just need to upgrade your firmware, then you can access the PSN to purchase and download games.
you just need to update the firmware, current firmware: 1.18 http://www.r4ds.cn/download/r4_v1.18_kernel.html
Fire up your WiiGo to optionsGo to settingsGo to the Wii System Update optionClick ok.Everything should take care of itself now. If you ever need a newer firmware version, just repeat steps 1-5.NOTE: You must have Internet access for this to work.