P-256 failing cases about micro-ecc HOT 2 OPEN

I see the same problem...
I can't verify the signature below using uECC_secp256r1
With these input rx also becomes = 0 during the uECC_verify process.
apply_z(tx, ty, z, curve); // Here tx becomes same value as rx so on the next line Z becomes 0 because rx and tx are equal
uECC_vli_modSub(tz, rx, tx, curve->p, num_words); /* Z = x2 - x1 */

I can verify the signature below with python using https://pypi.org/project/ecdsa/

HASH (SHA256): 797601B76D29603D167FA1062CC27B00BB0E39493BF3B7BBAFA610C2B24F4A20

Public Key:
7CF27B188D034F7E8A52380304B51AC3C08969E277F21B35A60B48FC4766997807775510DB8ED040293D9AC69F7430DBBA7DADE63CE982299E04B79D227873D1

Signature:
56CD9CF152BCCC3A64E41E2B2BF91ED0661E0821B14B50ABE93C05EA889AFED3F93452957106BAB410617E306D876BB58FA7D7B5A515AC6B6181D8D638651FC7

from micro-ecc.

@jojotds
I think the root cause is this line: uECC_vli_modMult_fast(z, z, tz, curve);
As soon as tz gets 0 once, it stays at 0 forever.

On a higher level, the issue is that this implementation is handling the identity element incorrectly. Let O be the identity element and P a point on curve. Usually O + P = P, but in this implementation O + P = O, which leads to the rejection of the signature.

In line 1579 to 1585, the point t is added to the point r. This point addition shows the above described behavior.
Probably this point addition algorithm has to be substituted with another algorithm, e.g. https://en.wikibooks.org/wiki/Cryptography/Prime_Curve/Jacobian_Coordinates

Please note this issue does not only exist for the inputs described above, but also for other inputs from test libraries (e.g. Wycheproof).

from micro-ecc.