It´s has leaked and are available to download from many torrents sites
iPad1_1_4.2_8C5091e_Restore.ipsw search It
BUT your "UDID" must be added by a DEV, otherwise will not the apple server response trying to update and It´s useless to try without the UDID.
Maybe if u knew a kindly dev that added your UDID, then u could Install It ! 
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