Let's play :
1 - Open the asus.com firmware dowload page (i prefer Chrome)
2 - Press F12
3 - Edit the "Global download" for the "ASUS Transformer Pad TF300T Firmware: V10.4.2.9 Only for US SKU (Android 4.1)" to :
<a id="DownloadContent1_Repeater1_Repeater2_0_DownloadUnit_0_Link_Global_0_link_0" class="word-darkblue-12-b" onclick="global_download(this ,'DownloadContent1_Repeater1_Repeater2_0_DownloadUnit_0_tr_ImgBox_0','DownloadContent1_Repeater1_Repeater2_0_DownloadUnit_0_div_ImgBox_0','20','16','0','9','ASUS Transformer Pad TF300T','WW_epaduser_10_4_2_9_UpdateLauncher.zip','EeePAD/TF300T/WW_epaduser_10_4_2_9_UpdateLauncher.zip','True','True','True','False','20')">Global</a>
(just change "US" with "WW")
4 - click on the link and.... :fingers-crossed: ...
funny ?