HTC One HSPA+ Problems | Philippine's SMART Network

[Guest joenefloresca]

Hello guys. I just got my Htc One and I'm new in this device. I bought it to someone rooted and unlocked.
I get it back to Stock Rom by flashing it Manually. 

I got HTC One 801n

My question is how come that I am not getting any HSPA+ signals? I live in Makati, I also tried
in Taguig and Paranaque but no luck. I am using Smart's LTE Micro Sim. I understand that I will not
getting LTE coverage from smart since their 1800mhz is not yet available, but HSPA+ should be working right?

I tried it anywhere and the speed I get is most of the time below 1 megabits. The fastest speed I got is 3 megambits but not stable
and for some specific place only. The seller told me that my HTC One came from US..

I'm wondering if I need to flash other radio firmware? Can you help me what Baseband version are you using and if you're getting 
a decent speed? I think getting below 1 mbps is not normal especially here in Makati and Ayala.

Here's my Software Info

Android Version : 4.4.2
HTC Sense Version: 5.5
Software Number: 4.19.401.8
HTC SDK: 5.68

Baseband: 4A.21.3263.04_10.38m. 1157.04L

If you're getting a decent speed what is your baseband? Thanks and Godbless!