Help Nexus 7 (2012) cannot update image fastboot or adb sideload

Hello Guys,

I'm trying to upload tgz image to my Nexus 7 (2012) as the bootloader got corrupted

Facts:

• Nexus 7 power on but halts on Google logo


• I can enter to fastboot or to adb recovery screen


• I downloaded latest sdk and google driver


• I try to run fastboot commands and suceed to errase "recovery"
  [*} I tried images: nakasi-lrx21p-factory-93daa4d3.tgz and nakasi-lmy47v-factory-b48bd71d.tgz


• I try to run the "fastboot flash recovery <recovery image> but I get the following error code:

• sending "recovery" < 380313 kb >


• okay [ 52.625s]


• writing "recovery"


• FAILED <remote: <InvalidSize>>


• finished. total time: 52.655ss

When I try the recovery mode it shows:
Booting failed with the Google Logo

I'm new on this kind of issues but I appreciate any help you can offer

Thanks,