Hi kumar && enjoy007,
Me and my friend we took a car and drove from LA to 2525 Otay Center Dr, San Diego, CA 92154 (near Otay Mesa Border). Parking is free at this location.
And there is a walkway to cross to Mexico border. I crossed the border by walk. Its just a 5 min walk. Once you get into Mexico there will be no checking or no border officer or no red stamps.
And I asked a nearby taxi driver about how to go to US Customs. He told me to cross the road(you can cross the road same like in India) and walk back.
I went to the POE and there is a 20 minute wait time. And the officer asked me the reason to come to US. I told him that I crossed the border today and coming back to get an updated I-94. He took both of the passports, I-797, looked at the Visa validity, asked basic questions like which company, what's your role and he simply swiped my passport and told me to get into the US.
I walked out of the building and verified I-94 online and its still showing the expired status. So I went back to another officer and told me I need a new I-94 for my H1 renewal. He gave me a I-94 slip and I went to the counter, paid $6 and got a blank I-94.
I was asked to go to I-94 renewal room and I waited for 30 minutes to meet a lady officer. She took both of my passports, entered the data onto the screen, became cautious suddenly and started whispering to the other officer saying that I-94 expired and it was showing 3 years(I was scared little bit as my I-94 expired 9 months back and could lead to 3 years ban).
I immediately reacted and gave I-797 copy which has I-94 validity, employment letter, my profile and my manager profile. The other officer looked at my I-797 copy and told this lady officer he has a valid 797 and I-94 and he was good to go.
I quickly filled out I-94 form and gave it to the officer. Now she started asking me when are you going to depart from US(my visa valid for 3 weeks only)???why you need new I-94? why you came to Mexico??
I took a breath and elaborated more about my situation. Said my passport expired, got new passport, employer filing for extension, need new I-94 for new Passport, going back and forth from India is expensive so came to mexico. Once i get an I-94, I will apply for extension. If approved, will go back to my country, get a visa and come back to US else will move to India. Finally she got convinced and I got tired explaining to her as she doesn't know much information about H1B extension.
Finally got the updated I-94. This whole process took 2 hours for me went to border at 9.30 AM came back at 11.30 AM.